基于正交各向异性材料的热传导方程，采用积分变换的方法得到了正弦调制激光辐照KDP晶体的瞬态温度场的一般解析表达式。同时通过Matlab软件仿真分析了调制激光的光斑半径、功率以及频率对KDP晶体瞬态温度场的影响。结果表明，正弦调制激光辐照KDP晶体时，晶体内温度随时间呈阶梯状变化，经过一段时间后最终呈稳定周期性分布，而且体内温度随激光光斑的减小、功率的增大而增大。上述结果可为把光热位移技术应用在KDP晶体的光热学测量提供理论依据。

A general analytical transient temperature field expression of KDP crystal irradiated by sinusoidal modulated laser is obtained by the integral transform method, based on the heat conduct equation of the orthotropic material. The influence of radius, power and frequency of the laser on the transient temperature field of KDP crystal is simulated by Matlab. The results show that the temperature of material has stepwise distribution with time, which shows periodical stable distribution after some time, and it increases with the decrease of the laser radius and the increase of the laser power. The above results provide a theoretical basis for the photothermal displacement technology used in the measurement of the opto-thermal parameters of the KDP crystal.