A novel micro in-pipe robot, which possesses the advantages of big driving force, fast and long-distance moving ability, is developed. The robot creeps bidirectionally and is driven by motors. It consists of self regulating mechanism, flexible holding mechanism, flexible shaft driving mechanism and unloading mechanism, which can adapt itself to micro pipelines with diameters ranging from 15 to 20mm. Based on the robot's operating principle and mechanism structure, dynamic characteristics of each mechanism are analyzed. The virtual simulation and prototype experiment results demonstrate that the robot can pass the elbows whose radius of curvature is not less than 80mm, move bidirectionally with a speed of 8-10mm/s, climb the oblique pipes angled 0-90°, and carry a load of at least 10N while the ratio of load to deadload is up to 6.67∶1.