Social TV ranked first among the top-ten most important science and technology chosen by University of Massachusetts in 2010.They pointed out that the audience could watch TV programs through smart-phones or computers. The audience could also use social networking sites such as Twitter and Facebook to follow the tracks of the latest news of stars, politicians and other public figures, while they take an active part in the discussion online, thus social TV is becoming more and more popular. The most representative social networking sites in China are Renren and microblog which attract mounting netizens. With the development of tri-network convergence, the development trend of television industry will be social TV. This paper will focus on the combination and convergence of television and social networking sites and will analyze the development of social TV from the following aspects: the meaning of social TV; the required elements for development; the basic patterns of social TV and the challenges social TV is faced with.