In order to study the characteristics of water-fed pulsed plasma thruster（WPPT） in operation process and to study the mechanism of energy distribution and influential factors of thruster performance

we proposed a new simulation model. This model has some merits of easy operation and high efficiency

which can quantitatively analyze the charged mass per shot and the impact of electromagnetic-aerodynamic coupling acceleration effect for the performance of WPPT. Numerical simulation was carried out on the foundation of the experimental WPPT of University of Tokyo. Results of performance parameters（such as impulse bit or specific impulse） show a good agreement with experimental data.It is revealed that only 20% of the total mass shot has the opportunity to be ionized and accelerated during discharge. The energy conversion efficiency that the acceleration energy is converted to the initial st

ored capacity energy（E

0

=13.5 J） of WPPT is 40%

among which 14% is used for electromagnetic acceleration. Finally

influences of variations of electric parameters and configuration parameters on thruster performance are studied to guide WPPT design.