在惯性约束聚变（ICF）实验研究中，三次谐波转换单元是ICF驱动器重要的组成部分，为了缩短晶体的在线调试发次与时间，需先对单元进行离线调试。其基本原理是，通过扫描、测量倍频和三倍频晶体在不同倾斜角度下的谐波转换效率，然后利用多项式函数拟合数据，绘制谐波转换效率随倾斜角度变化的调谐曲线，确定最佳匹配位。基于理论分析，设计了一套高精度、自动化的三倍频离线调试系统。通过对现有系统的改进实验，以及对结果的分析表明，系统自动工作性能良好，单点测试的重复精度为±30 μrad，能量测量精度达到4%。

The third harmonic generator is an important part of the ICF laser facility. It is necessary to adjust the KDP crystal alignment offline before it works efficiently online. The basic process of the adjusting is to measure the harmonic generation efficiency at different detuned angles by scanning the crystal, then fit the dates with multinomial function, and draw a rocking curve and decide the best angle for the harmonic generation. In this paper, a precision and automatic crystal alignment adjusting system is designed base on the theory analysis. In the experiment, the system can adjust the crystal alignment automatically, and it has an accuracy of 30 μrad in phase matching angle measurement, and 4% in conversion energy measurement.