Abstract: In order to solve the problem of measurement error and blind zone because of light obstruction and obtain a satisfactory 3-D shape of in-pipe surface, a novel 3-D shape inspection system for in-pipe surfaces was proposed. The system was set up with a circular structured light to illuminate vertically and dual complementary metal oxide semiconductor cameras to record images simultaneously. Image process algorithm and calibration method for the inspection system were founded. The results of verification experiment show that standard deviation of the system is 0.50mm. The system has good ability to solve the problem of blind zone, reduce the measurement error, and obtain whole 3-D shapes of in-pipe surfaces.