叙述了测量微观不平度的90°相移激光干涉仪的原理和构成。对这种新型干涉仪的性能及有关问题作了讨论。测量结果的计算和样品扫描的控制，由个人计算机完成。垂直分辨率达1um，横向分辨率达10μm。实验结果证明了系统的稳定性。 The principle and structure of a 90 ° phase-shift laser interferometer for measuring microscopic roughness are described. The performance of this new interferometer and related issues are discussed. The calculation of the measurement results and the control of the sample scanning are done by a personal computer. Vertical resolution of 1um, horizontal resolution of 10μm. The experimental results show the stability of the system.