A statics analysis model of the transmission system is established for the power split- torque transmission system of double input cylindrical gear,the factors of the meshing deformation of the gear pair,lateral deformation of a gear centre,duplicate gear shaft torsional deformation,gear installation error and support stiffness are considered in the model. According to the equilibrium conditions of force and moment,and the characteristic of the closed loop structure,the deformation coordination condition of the system,the statics equilibrium equation of the system is established and the branch load sharing coefficients are obtained. At the same time,the effects of the installation error,installation angle,duplicate gear shaft torsional stiffness on the load sharing coefficient are investigated. The results show that the error has a cumulative effect and the load sharing coefficient increases significantly when the error is increased,and the effect of errors of synthesized torque stages on load sharing coefficient is more than split torque stages. In this set of parameters,the load sharing coefficient is equal when input installation angle is about 166°. Reducing the duplicate gear shaft torsional stiffness is helpful to improve the load sharing performance. Furthermore,rational allocation installation angle of split torque stages and difference of duplicate gear shaft torsional stiffness are conducive to further improve the load sharing performance.