The definition of stability and repeatability of the laser frequency and factors affecting the stability of laser frequency were analysed . the normal methods used to stabilise frequency and produce double - frequency were explained . after analysing the working conditions and related parameters of the laser device , it was concluded that the laser tube should be put inside an insulating cover and an electric discharge tube with a bigger diameter and length , smaller wall thickness and a higher thermal conductivity coefficient should be chosen 分析了激光频率的稳定性、复现性的定义及影响激光频率稳定的因素；介绍了常见的稳频及产生双频的方法；分析论证了激光器双纵模热稳频的使用条件和有关参数的关系，得到结论是：应将激光管装在保温罩内；选用放电管直径及长度大、壁厚小、材料导热系数大的放电管。
