Regarding that the potential risks of affiliated brokerage house to buy as well as to sell the commitment underwriting stocks. This paper investigates whether the affiliated analysts have biased earnings forecasts or recommendations of underwriting stocks before and after the underwriting period. Using Taiwanese data from 2007 to 2010, we extend the research of Lin, McNichols and O’Brien (2005) and explore the relationship between the firm commitment underwriting and analyst’s investment recommendation. The empirical findings show that the affiliated analysts have more commitment purchasing stocks tend to give more optimistic ratings of underwriting stocks. After finishing underwriting, we also find that the positive relationship between favorable recommendation and purchased underwriting stocks of affiliated analysts. Therefore, our study indicates that the affiliated analysts have incentives to make stock recommendations not only before but also after underwriting.