The new rule has been implemented to "prevent vulgar content, base art forms, exaggerated violence and sexual content in Internet video having a negative effect on society," China's State Administration of Press, Publication, Radio, Film and Television (SARFT) said on its website on Monday.
Online video sites are often a lodestone for comment and critique on social issues in China, with users uploading videos documenting corruption, injustice and abuse carried out by government officials and authorities.
Neither Youku Tudou nor Renren were available for immediate comment.
Last year the Communist Party began a heavy-handed campaign to control online discourse, threatening legal action against people whose perceived rumours on microblogs such as Sina Weibo are reposted more than 500 times or seen by more than 5,000 people.
Rights groups and dissidents criticised the latest crackdown as another tool for the ruling Communist Party to limit criticism of it and to further control freedom of expression.
China has attempted to implement similar real-name registration rules, including when buying SIM cards for mobile phones and signing up for Tencent's WeChat mobile messaging app and microblogs.
However these have proven difficult to implement and easy to avoid for China's tech-savvy Internet population.China's Internet regulation system is mired in bureaucracy and overseen by a number of government agencies, including SARFT, the State Council and the Ministry of Industry and Information Technology, which can lead to conflicts of interest between these bodies.