Abstract: According to the special technical features of the oil pipelines in Bohai Sea and the requirements of the program, an allposition hyperbaric TIG welding robot for underwater pipeline recovery work in deep water of 60-100 m was developed.In its control system the harmony and management of multi-controllers was achieved by adopting PPI agreement. The parameters of command movement and that of welding movement for the welding robot were controlled.By a man-machine conversation system, the controls of the robot, welding states and scenes could be manipulated and supervised.The unmanned welding problem in hyperbaric circumstance was solved at the same time.Under the different pressures, such as 0.1 MPa, 0.3 MPa, 0.5 MP and 0.7 MPa, the welding simulations had been done with a 16Mn steel plate and the better effect of one side welding with back formation was obtiained. Experimental results show that a higher control level and remote control by adoption in a robot are the key techniques of TIG welding in high-pressure air condition.