Abstract: In this paper,numerical integration is used to calculate and predict the orbit of one of the Martian moons,Phobos. First,the considered force models,parameters and integration methods are introduced. Then the effect of different force models and parameters are analyzed by simulation,and a suggested model is given according to the analysis result. Finally,the difference in position and orbital elements between the proposed model and existing ephemeris is compared. The result shows the same order in magnitude in comparison with the difference of the ephemeris themselves,which proves the precision and reliability of the proposed model. The Phobos dynamical force models analysis and the orbit prediction will help to the exploration missions of Phobos.