Abstract: The range finder and position shift observation based on laser interfering has been widely applied with the tendency of portability, intellection and integration. However, the present laser interfering devices for distance measurements are mostly based on Michelson interferometer. The interfering information is processed in the spatial domain. Sometimes the signal is probably influenced by the turbulence and the vibration introduced by large industrial equipment. Therefore, a kind of new measurement based on laser heterodyne interfering was proposed, which could transfer the signal process to the time domain in this article. In this system frequency-modulated laser beam was split into two interferometers. The detector received the beat signal and averaged the signal at the time domain and the computer demodulated the signal in the frequency domain. The testing results appeared as good robustness, and the testing error could be controlled within 0.01 mm.