Provided are a method and an apparatus of optical module assembly, where the method includes: when an optical module to be aligned images, controlling an alignment mechanism clamping a lens to be assembled to move in a set direction by a set movement step; when the alignment mechanism moves each time, collecting light spots imaged by the optical module to be aligned sequentially, and selecting an estimated light spot with a minimum size from the collected light spots; searching for an ideal light spot with a minimum size according to a reduced movement step and the estimated light spot with the minimum size; determining a movement position of the alignment mechanism when the ideal light spot with the minimum size is collected as an optimal position of the alignment mechanism; and controlling the alignment mechanism to move to the optimal position to align the lens to be assembled.