This paper aims to study the influence of bolt preload distribution on structural performance in the bolted connection structure model of pitch bearings of wind turbines. The preload application deviation and the change of contact stress of the rolling element of the pitch bearing were analyzed by finite element modeling. The results show that the bolt preload loading deviation will cause the rolling element contact stress of the pitch bearing to fluctuate, and the rolling element contact stress near the blade is greater than the rolling element contact stress far away from the blade. In the case of large fluctuations in preload, the contact stress fluctuations of the lower rolling elements are more affected. Therefore, in order to extend the working life of pitch bearings, the bolt preload should be precisely controlled during assembly.