A nonlinear dynamic model of 2K-H type of planetary gear train was developed. The model takes into account the sliding friction force, time-varying mesh stiffness, gear mesh errors as well as gear backlashes. Relative displacements between meshing components were derived to analysis realistic mesh force. Arms of friction force of different meshing gear pairs were deduced in consideration of the number of meshing gear pairs regularly varying in meshing zone. The effect of friction force in contact zones for two tooth pairs meshing of system with multi degrees of freedom were considered. System dynamic differential equations which are multi-backlash, variation parameter and multi-DOF are derived. At last, system multi-degrees of freedom non-linear differential equations are solved by variable step-size Gill integration method. And vibration responses of the system with the influence of sliding friction force are calculated.