On the basis of 92 listed companies' empirical data from Shanghai Stock Exchange between 1993 and 2003,this paper studies the change of performance after ERP implementation through the methods of Wilcoxon Signed Ranks Test,Panel analysis and coefficient constraint test.The results show that we can't draw the conclusion of whether there exits the "productivity paradox of Information Technology" caused by ERP implementation and that there exists Performance dips in the ERP implementation year and ...