Abstract: The moving speed of the numerical control machine tool and the three-COMERO has reached 1 000 mm/s. However, the present measurement speed of the commercial heterodyne interferometer can not meet the requirement of measuring the moving speed. A High precision and high measurement speed dual-longitudinal thermal frequency stabilization laser interferometer is presented. This interferometer uses a laser of 206 mm-long and beat-frequency 728 MHz and a high frequency oscillator of high stability to get AC counter pluses. Experiments are set up to testify the measurement speed and precision of the interferometer. The system's precision is 0.1 μm /800 mm. Results show that this kind of interferometer can be used to measure the displacement of an object whose velocity is 1 000 mm/s.