Abstract: Propellant refueling is necessary for the long-term operation of space stations. Refueling of the propellant tank is a key process since it relates to both the cargo spaceship and the space station, besides, there is liquid propellant flowing between two spacecrafts. Many propellants are toxic, however, the flow experiments on the ground usually use nontoxic liquid instead of toxic propellant in case of leakage. Because the physical characteristics of the nontoxic liquid are different form those of the real propellants, their flow properties are also different. In this paper, a numerical model is built for the refueling course of a propellant tank, and the simulation results are compared with the experimental data using pure water, in order to validate the accuracy of the numerical model. The refueling courses of real propellants, MMH and MON-1, are investigated and compared to that of pure water. It is found that the volume flow-rate of MMH is higher than that of pure water, while that of MON-1 is lower than that of pure water.