Abstract: The tightness of the docking channel formed after the docking of manned spacecrafts is essential for the sealing performance of the whole assembly. In order to ensure the safety of the astronauts, the leak rate detection of the docking channel is required before the hatch is opened. Based on the characteristics of the docking channel, a pressure-maintaining leak detection method is proposed with temperature corrections. This method determines the assumed maintaining pressure and the time for the leak detection, which is also validated by the ground simulation test. It is shown that this method is has applicable with an adequately high precision. The flight verification of this method in the Tiangong-I has provided the technical support for the leak detection in the following space station missions.