The invention relates to the technical field of lamps, in particular to an RGB all-laser light source module and a light path adjustment method thereof. The RGB all-laser light source module comprises a light source part, a coupling part, a transmission part, a light divergence part and a collimation part, wherein the light source part is used for emitting laser beams; the laser beams comprise a green laser beam, red laser beams and blue laser beams; the coupling part is arranged on light axes of the laser beams, and used for coupling the green laser beam, the red laser beams and the blue laser beams to form a first coupled light beam; the incidence end surface of the transmission part is arranged at the convergence point of the first coupled light beam; the first coupled light beam is transmitted by the transmission part to the light divergence part; the first coupled light beam is diverged by the transmission part to form a second coupled light beam; and the collimation part is arranged on the light axis of the second coupled light beam, and used for collimating the second coupled light beam. The RGB all-laser light source module has the advantages that the output light beam being high in color uniformity, illumination uniformity and etendue can be obtained; the structure is compact; and the light energy utilization ratio is high.