The main purpose of this study was to examine the impact of IFRS adopted by companies with shares listed on the Taiwan Stock Exchange or traded on the Taiwan GreTai Securities Market or Emerging Stock Market in 2013 to corporate performance evaluation. Questionnaire survey was used in this study in 2015. The survey objects are IFRS financial managers of listed companies. in order to understand the business status after converting IFRS two years later. The results analysed by one-way ANOVA , SPSS. to investigate the influence of independent variable, IFRS conversion company size (turnover, number of employees and the number of years of incorporation) on dependent variable,business performance assessment. The results showed that the performaces of companies are significantly affected by IFRS conversion, which company the overall turnover and have been established for 20 to 35 years