A mathematical model of the priming process of propellant pipelines was presented based on one-dimensional fluid theory using the method of characteristics (MOC) and finite deference.Coordinate transformation technique was employed to change fluid motion in time-dependent domains to ones in time-independent domains.The details of the method were presented with an illustration of the priming process of a simple piping system (system consisted of a tank

a pipe and a isolation valve).The results exhibited greater consistency with conventional method of characteristic calculations.The influence factors to the surge pressure of priming process have been studied future.The results show that the surge pressure can be effectively reduced by increasing the initial gas pressure

decreasing the tank pressure and increasing the polytrophic exponenting.