Abstract: In order to insure that autonomous underwater vehicle completes the tasks successfully in unstructured and hazardous oceanic environment with the high pressure and low visibility, an efficient and effective fault-tolerant control system becomes imperative for AUVs. This paper discussed thrust fault-tolerant control technology for ZHISHUI Ⅲ AUV, designed at Harbin Engineering University. A decoupling controller and an approach to the allocation of thruster forces of an AUV are investigated first, then a fault-tolerant control approach under thruster fault is given. Results from computer simulation show that the precision of the fault-tolerant control approach is satisfactory.