The bearing capacity of the tack roller needle roller bearing is directly determined by the its bolt strength. The design parameters of oil injection hole are one of the main factors affecting bolt strength. To solve the problem, an optimization design method for the bolt of a tack roller needle roller bearing is proposed. In the method, a parameterized model of the tack roller needle roller bearing is established by using a 3D modeling software. Then, the finite element simulation model of tack roller needle roller bearing is established by using the finite element method; and the influences of oil injection hole and bolt fillet design parameters on the bolt strength are analyzed. Finally, a multi-objective optimization model of tack roller needle roller bearing is established by using response surface method; and the optimal objective is the minimum stress and deformation. Moreover, the optimal design parameters of the bolt injection hole and bolt fillet are obtained. The results show that the stress and deformation of the optimized tack roller needle roller bearing can be reduced, which can provide some validation for the proposed method.