The design and experimental research of high-brightness uniform pump coupling system are carried out for the characteristics of Yb∶YAG slab gain module.Theoretical calculations show that the power density of the pump is related to the laser extraction efficiency of Yb∶YAG.In order to improve the pump brightness,the spatial/polarized composite splicing method is used to combine the four LDs.After the experiment was completed,the total power of the laser diode was 25 kW,and the combining efficiency was about 90 %.The proven structure effectively solves the problems of the current power and efficiency degradation of the Yb∶YAG strip laser crystal due to low pump power.