Abstract: According to different forms of gear power split transmission including parallel axes,star gear train and planetary gear train,a new type of spiral bevel gears power split system with cross axes transmission was proposed and its structure and working state was explained.The transmission powers of every gear pair in the system were then calculated,and the power split situations were analyzed under conditions of all kinds of installation errors.The results show that,in consideration of the installation errors in shaft angle of input gear and its opposite output gear or axial error of its adjacent output gear,the power transferred by main load gear pair of the system can be decreased,so the load capacity of the system is improved obviously,contributing to uniform load of the system.When every gear has different installation errors,the load situations are influenced by the error accumulation and opposition.