The solid-state laser generated by using the LD direct end-surface pumping technology can be used in complex airborne environments, and it has high research value in engineering application. The static laser output with high light conversion efficiency can be obtained through the successful study of the design method of the high-efficiency LD direct end-surface pumping technology, which is of great significance to the subsequent realization of the high-energy LD end-surface pumping laser illuminant. This paper focuses on a kind of 20 Bar LD array with vertical and even distribution, and two kinds of optical coupling systems of quadrangular prism are simulated and designed by using ZEMAX software. The pump light of the end-surface pumping array is focused into the working substance by using the coupling system.The beam focusing positions of the two coupling systems are different.By changing the focusing position, the output status of laser energy in different states is studied. The experiment goes as follows:in view of this flat-flat cavity configuration and with the size of the working material (1at%) being 4 mm×4 mm×10 mm, the pump light is designed to evenly illuminate the front surface of the working material and the distance from the focus to the front surface of the working material is designed to be 5.5 mm.The result shows that at this timethe mode matching degree between the pump light and the oscillation light is the highest, in which state the maximum light conversion efficiency of the LD direct end-surface pumping solid-state laser can be as high as 40%.