Group buying is a new shopping mode which, as its name implies, means a large group of people buying the same product. It aims at enhancing buyers' negotiation power with sellers to get a favorable price. With the prosperity and development of Chinese ecommerce, online group buying is popular among Chinese Internet users and has become the main form of group buying. It is convenient, fast, low in price and unrestrained by regions. Currently many websites in China are trying to launch group buying service and flourish quickly, such as Juhuasuan, Nuomituan. It is known that the majority of online group buyers are young people in large and medium-sized cities in China.