Web sites are very important and companies can attract customers by promoting various features of the web site. This paper presents an analysis of the relationship between web site functions and firm performance. A research model based on the DeLone and McLean (D&M) model and customer service life cycle (CSLC) theory was used to investigate the impact of web site functions on e-business success. The research model considers web site functions, web site use, customer satisfaction, and firm performance. According to the CSLC theory, there are three stages in a customer service life cycle. Therefore, the web site functions are divided into three stages: requirements, acquisition, and ownership. The functions in each stage serve to encourage usage and thus, enhance customer satisfaction and firm performance. The theoretical model and hypotheses were tested using data collected from 72 wholesale and retail firms in China using the partial least squares (PLS) method. The results suggest that web site functions in the acquisition stage have the strongest impact on web site use and that the improvement of customer satisfaction can significantly increase firm performance. Web sites are very important and companies can attract customers by promoting various features of the web site. This paper presents an analysis of the relationship between web site functions and firm performance. A research model based on the DeLone and McLean (D & M) model and customer The research model considers web site functions, web site use, customer satisfaction, and firm performance. According to the CSLC theory, there are The functions in each stage serve to encourage usage and thus, enhance customer satisfaction and thus, enhance customer satisfaction and firm. and hypotheses were tested using data collected from 72 wholesale and retail firms in China using the partial least squares (PLS) method. The results suggest that web site functions in the acquisition stage have the strongest impact on web site use and that the improvement of customer satisfaction can can significantly increase firm performance.