Evidence from the developed capital markets shows that underwriter reputation can be used to re-strain the earning management of IPO companies． This restraining relationship is reexamined with the samples of IPO companies from 2001 to 2011 in China． A different result is found that underwriter reputation is ineffec-tive in restraining the earning management of IPO companies，and that the positive relationship between them is significant under the poor investor protection areas． Moreover，in order to get a higher underwriting fee，the higher-reputed underwriters may even help the IPO companies to gain a larger room in earning management．Obviously，in order for the mechanism of underwriter reputation to work effectively，China’s market needs to be better self-disciplined，and the legal risks needs to be raised against the opportunism behavior of the under-writers especially．