The utility model provides a small -size three -dimensional adjusting device for light path adjustment which characterized in that: including round platform form adjust seat, wedge -riser flange dish,photoelectric detector and three before constitute to the bolt to the screw, after three, precedingly adjusting the seat to the round platform form of screw in three -dimensional adjusting device andbeing connected to the emergent light end of treating complex light outgoing device, the back is connected to the wedge -riser flange dish on the round platform form adjusts the seat to the bolt, andphotoelectric detector utilizes the internal thread that its external screw thread and wedge -riser flange coiled to be connected. This three -dimensional adjusting device through before adjusting toscrew, back to screw, back to the nut, can change the three -dimensional spatial position of photoelectric detector photosurface fast, make the photosurface can receive exiting light beam rapidly. The utility model discloses a small -size three -dimensional adjusting device for light path adjustment has simple structure, and three dimensions control range is big, and it is convenient to adjust, light path adjustment accomplish and fixed after be difficult for receiving vibration effect and change the light path, advantage such as with low costs.