Provided are a surface light emitting module for an LED light source, a vehicle lamp using the same, and a method of assembling the same, so as to solve the technical problem that the existing LED light emitting module cannot achieve uniform lighting and cannot be used for the high brightness function as a brake lamp, a turn signal lamp, or the like. The surface light emitting module for an LED light source described in the present disclosure comprises: a back plate, a light guide plate, and an optical film disposed sequentially from back to front; and specifically, an LED light source and a PCB are disposed on a side of the light guide plate, and a plurality of concave/convex microstructures are disposed at intervals on the light guide plate.