Impulse coupling effect of short pulsed laser ablation the target has great application in the fields of laser ablation micro-thruster and laser orbital debris removal. High precision impulse measurement is the necessary method in studying the impulse coupling effect. The torsion pendulum with laser interferometer method was put forward and the measurement system was constructed. In light of the problems of vertical axis vibration and existing error angle in the initial state of torsion pendulum, the high frequency vibration will lead to the non uniform spacing in laser interference fringes, besides, the initial angle will lead to the bright stripe advancing, these two factors will lead to the low measuring accuracy. An impulse experimental data analysis method was put forward based on ordinary least squares techniques, which can remove the high frequency noise effectively. The method can solve the problem of low measuring accuracy and improve the micro impulse method.