Neck lumbar traction bed is through the computer control motor and hydraulic transmission device, implementation of traditional Chinese medicine traction, Angle rotation and manual reduction action of a device, etc. Saving time and effort can well meet the needs of the treatment on lumbar disease. Based on the failure phenomenon of traction bed hydraulic transmission device, the composition and working principle analysis of the hydraulic system, concluded that failure of the hydraulic transmission device is due to the pressure gauge damaged or blocked between the tubing and the overflow valve, which allows users to quickly troubleshoot.