采用有限元分析方法对KTP晶体内部3维温度分布情况进行了精确计算。根据参量过程满足的能量守恒条件和动量守恒条件，利用KTP晶体的热光色散方程计算了参量过程中温度对相位匹配角、光波走离角、允许角及晶体的有效非线性系数的影响。结果表明：晶体内温度分布不均匀；在沿着通光方向上晶体截面温度分布不同；加强晶体表面冷却效果，可有效降低温度对相位匹配角、光波走离角、允许角及晶体的有效非线性系数的影响。

The temperature distribution inside KTP crystal was calculated by the finite element analysis accurately. The phase matching angles, walk-off angles, tolerance angles and effective nonlinear coefficient of type II KTP crystal were calculated according to the conservation of mass and phase matched for parametric process and the thermo-optic dispersion of KTP crystal. The results showed that the distribution of temperature inside crystal was non-uniform. Along the direction of light, the temperature distributions of section of crystal were different. To strength the cooling effect of crystal can effectively reduce that the temperature influenced on the phase matching angles, walk-off angles, tolerance angles and effective nonlinear coefficient of crystal．