Under what conditions can a large scale national protest movement form in China?

No national protest would ever be allowed by the Chinese Communist Party; it is too likely that it would spin out of control and become a threat to the People's Republic. That is what happened 24 years ago in Beijing, and the party will not let it happen again.

Protests aren't always forbidden, even on a national scale. Consider last fall's anti-Japanese protests that were triggered by the purchase by the Japanese government of the Diaoyu/Senkaku Islands from their private owner in Japan. These protests (and the rioting that followed) was allowed to take place because it served the interests of The Party. Remember, it was not too long before this debacle started that Gu Kailai was convicted of murdering Neil Heywood. Think of The Party as a man standing in front of a fire with a fan and a fire hose. He fans the flames when he needs to and adds water when they rise too high. One of the concerns during these protests was that the fury the people were displaying towards the Japanese might end up getting directed at The Party itself.

While I am as far from being a fan of his as only possible, there is no better credentionalized expert in large-scale protests than http://en.wikipedia.org/wiki/Vladimir_Lenin. And he teaches to look for disenfranchised public but also for dysfunctional rulers. While there could be many reasons for the general public to become really frustrated - deaths from pollution, gender imbalance, inequality - as long as Communist Party can drive economy as well as promote competent cadres and execute effective policies internally, they'll keep their people under control.

No national protest would ever be allowed? It's not true. The Communist Party of China loved national protest in its history. First, at the beginning of the establishment of People's Republic of China, there were many national event of protesting against the USA's invasion on Cuba, USA's invasion of Korea, etc. Second, during the Culture Revolution, Chairman Mao was a master of utilizing of national protest to mobilize the public to crash his colleagues.

"large scale national protest movement" not so easy to happen in china,but "large scale regional  protest movement"really do happen many times almost every year and this is a increasing  tendency in the future of china, more and more Chinese citizens become less tolerant to the corruption ,non-democracy,abuse the power the government and etc.

Thanks for the A2A,First, it’s a common misconception outside of China that all manner of protests are banned. In fact, hundreds of protests take place across China almost daily. It’s just that they’re usually small-scale and local in nature. The targets of these protests are usually things that directly affect the quality of life and well-being of the protestors, such as corrupt local officials, heavy-handed local policies and taxes, environmental pollution, and developers who seek to confiscate farmers’ land. But the question asks about large-scale national protests, so these small-scale protests are besides the point. I disagree with the other answers which say large scale national protests in China are impossible. No, they’re not, it just depends what the target of the protests is. Protests against the central government, against Chairman Xi, or against the Party absolutely are not tolerated and will be suppressed immediately. But protests against other targets I believe are definitely possible. In fact, they might even desired by the central government.I’m talking, of course, about protests against targets such as Taiwan, Hong Kong, Japan, or the United States, countries (districts) that provok the ire of Chinese nationalists. As the Chinese economy sputters and people see their options in life come under pressure, expect to see more protests of a nationalist nature. These protests may appear to be formed from the grassroots and not formally organized by the government, but trust that if they take place, it is because the government allows them to do. The reason, obviously, is that the government sees such nationalist movements serving the purpose of distracting people from their economic woes and the government’s mismanagement of the economy.I also wouldn’t be surprised to see national protests against certain party figures or captains of industry, provided those persons are first designated targets of Chairman Xi’s anti-corruption campaign. I’m describing of course a situation resembling the anti-rightest movements of the 50s and Cultural Revolution of the 60s. The central government in the past has allowed nationalist protests against Japan and other sanctiond targets, only to see them get out of control, at which point they are cracked down upon. So don’t expect this to be a clearcut or easy process. But these are unprecedented times, so expect these tensions to play out.

<<The law of the people's Republic of China on the assembly and demonstration of the people's Republic of China>>Fourth articleWhen citizens exercise their right to assembly, procession and demonstration rights must abide by the Constitution and the laws, shall not oppose the basic principles specified in the constitution. No damage to the state, society, the interests of the collective and other citizens of the legitimate freedom and rights.Seventh articleTo hold meetings, demonstrations and demonstrations, the competent authorities in accordance with the provisions of this Regulation shall apply for and obtain a permit. The following activities do not apply:1 held or held in accordance with the state decided to celebrate, commemorate and other activities;2 state organs, political parties, social organizations, enterprises and institutions shall, in accordance with the laws and regulations of the organization.Twelfth applications for the assembly, procession and demonstration, one of the following circumstances, shall not be permitted:1 against the basic principles established by the constitution;2 harm to national unity, sovereignty and territorial integrity;3 to incite ethnic divisions;4 a meeting, a demonstration or a demonstration, which is held by an application to be held in full, will directly endanger public safety or seriously disrupt public order.