Abstract: There is a lot of gas and liquid pipe equipment in a manned spacecraft pressure module. The on-orbit maintenance of the pipe equipment can improve the lifetime and reliability of the manned spacecraft significantly. In this paper, a method of the on-orbit maintenance of the pipe equipment in a manned spacecraft pressure module is proposed, and applied in an on-orbit maintenance program for a regenerative life support pipe equipment. With a sufficient verification on ground, the program is carried out by astronauts in a manned spacecraft. It shows that the method is effective. The method can be used in the design of the on-orbit maintenance in a manned spacecraft.