对LD端面泵浦分离型激光放大介质的热效应进行了分析和研究；建立了Cr,Yb:YAG/Yb:YAG复合结构的热传导模型。采用有限元分析方法得到了介质内部的温度分布，给出了介质折射率随温度变化的计算方法并得到了出射端面波前相位分布随温度变化的情况。计算结果表明：保持泵浦光功率密度不变，在不同的泵浦时长下，介质温度以及通光方向截面折射率变化也不同。随着泵浦时间的增长，介质的温度和折射率也增大，出射端面激光光束的相位畸变同样增大。当泵浦光功率密度增大时，温度与折射率的变化趋势与泵浦时间变化时的情况较为相似。热效应随着泵浦时间的增长和泵浦光功率的增大都变得越来越严重。

The thermal effect of LD end-pumped rectangular separated laser amplifying medium was analyzed and studied. Thermal conduction model of Cr,Yb:YAG/Yb:YAG composite structure was established. The temperature distribution inside the medium was calculated by utilizing the finite element method. The computing method of the medium refractive index vary with temperature was given, and worked out the output end face wave front phase distribution change with temperature. The results reveal that, while the pump power density is unchanged, with different pumping time the temperature distribution and refractive index at the direction of the optical section are different. With the increasing of the pumping time, the temperature and refractive index also increases, the output end face wave front phase distortion enlarge as well. While the pump power density increases, the variation tendency of temperature and refractive index are similar to the situation while the pumping time changes. The thermal effect becomes more serious as the growths of pumping time and the increases of pump power density.