Abstract: The in-pipe surface defect inspection is very important for pipe maintenance and repair. An pipe inner surface 3D vision inspection system was proposed based on the vision principle by using circular laser projector. Firstly, the principle of the circular laser light vision was given, and the in-pipe 3D vision inspection system based on the axial pattern was proposed aiming to the restricted space of the inner pipe. According to the characteristics of the inner pipe inspection system the planar target was designed with which the calibration of this system was completed. Finally, the industrial pipe's inner surfaces were inspected based on the proposed circular structured light system, and the 3D shapes of in- pipe surfaces were reconstructed. Experimental results indicate that the system's calibration precision is 0.081 mm and the measurement system proposed in the paper is suitable for the industrial pipe inner surface inspection.