The stock price performance of the IPOs of common stock listed on Taiwan-stock-exchange and the Over-the-counter market in Taiwan was studied, the period was from January 2014 to August 2017.Using Event study to test stock price performance after the IPOs one month and six months trading days. The empirical results show that the abnormal returns in the short run were existed of the IPOs of common stock on Taiwan-stock-exchange and on Over-the-counter. Moreover, after controlling the factors of the new underwriting system, it is discovered that most of the common stocks listed on Taiwan-stock-exchange and Over-the-counter market possesses short run positive abnormal returns in the initial stage. It is showed that the investment performance of the IPOs in Taiwan were affected by the new underwriting system.