Online reputation mechanisms have been found to be an effective way to ensure honest behavior from the seller in c2c. At the same time, it has also been regarded as an important platform where large-scale of word-of mouth behavior and evaluations of the purchase experience could be communicated. There are altogether two kinds of evaluations in Taobao reputation systems: evaluation and feedback. Thus, reputation systems including buyers’ evaluation and feedback become an important reference to other buyers when deciding whether to buy from the seller or not. The aim of this study is to have a comprehensive understanding of the antecedents and motivation of the participation in different conditions after each transaction. Interview has been conducted to help us to find out the main antecedents. We found that factors such as satisfaction and psychological factors will have a potential impact on evaluation making, factors such as altruism and satisfaction will have a potential impact on feedback submission. A survey will be conducted and the potential respondents would be Taobao buyers who have real online shopping experience. We will demonstrate how these factors including psychological factors and satisfaction lead to different style of participation in Taobao reputation systems.