Abstract: Due to the atmospheric drag, some amount of propellant is required for the orbit maintenance of a space station, and the propellant refueling is necessary. The propellant purge, as an important part of the propellant refueling technology, is an essential condition for the space station mission. The research progress abroad of spacecraft liquid venting on orbit is reviewed in this paper. The influences of the temperature, the stagnation pressure, the vapor pressure, the gas content in the liquid, and the jet shape and size on the flow pattern are evaluated for the liquid ejected into a vacuum. Based on the review and considering the characteristics of the propellant on-orbit venting, some suggestions are made for the scheme design of the propellant purge for the China's space station.