Abstract: With ray tracing method,a calculating model of laser diode directly side-pumping method is proposed,and the gain distribution characteristics in the active medium side-pumped by diode bars are studied.The effects of system parameters change on the homogeneity are analyzed.The fluorescence distributions of the active medium are tested with CCD for three different side-pumped construction.The experimental results agree well with the results of the calculation of this model.This model can completely be put into practice.