Influence of alignment errors on the meshing of involute spiral bevel gears using FEM is investigated in this paper. 3D geometrical models of involute spiral bevel gear drive are computationally designed and the reliable non-linear finite element contact models are also developed. Furthermore, based on the valid 3D FE models, simulations of meshing of loaded spiral bevel gears with four types of alignment errors are performed. The influence of four types of alignment errors on contact stress, transmission error and shift of path of contact has been discussed in detail. The results demonstrate that the alignment errors have different degrees of adverse effects on the load-carrying capacity and the smoothness of transmission. Therefore, the study provides useful reference for the modification design and the assembling of spiral bevel gears in practice.