Based on the data from 2004 to 2016 in Chinese IPO market, we divide the sample into four GROUPs, which are large companies with a large underwriter, large companies with a small underwriter, small companies with a large underwriter, small companies with a small underwriter. We examine the post-IPO performance of these four GROUPs, and figure out whether the “big-one alliance” (large companies with a large underwriter) is really the best. We find that:(1) “big-one alliance” is not the best, but the long term performance is relatively good. (2) the post-IPO performance of small companies with a large underwriter is better than others. (3) The post-IPO performance of large companies with a small underwriter is the worst, and the higher the underwriting fees, the worse the performance, which validates our theory of collusion. Our research contribute in: (1) sending the message to the public that the “big” is not always equal to the “good; (2) finding that the combination of underwriters and firms is an effective signal; (3) confirming that in the Chinese IPO market, the underwriter has a function of finding valued firms.