Abstract: For a space station with several cabins or a single cabin, docking with a spaceship or other vehicles, may suffer from insufficient power supply due to the fact that it is out of position or they are shadowed from each other. It is therefore necessary to have a parallel operation power supply for the space station. This paper discusses the parallel operation power supply for the Tiangong-I and the Shenzhou spaceship, where the power is transferred to another cabin through a redundant parallel output and with an automatic current-sharing control. By comparing and analyzing the foreign parallel-operated power supply projects and the characteristics of the International Space Station, ISS-Zarya and MIR, some general projects of the parallel operation power supply for space stations are discussed, and a feasible parallel operation scheme for China's future space station is put forward in the end.