Abstract: In order to solve the testing problem of muzzle vibration signal with complex frequency distribution under the abominable circumstances with the shooting of barrage weapons, the photoelectric detection method based on line laser speckle field was used. The mathematical relationship between the vibration signal and output current was studied, and the noise and amplitude frequency characteristics of photoelectric detection circuit based on avalanche photo diode were analyzed. A method of muzzle vibration measurement based on laser speckle effect of barrel surface was proposed. The detection experiment of vibration signal was carried out at distance of 25m, with amplitude of micron magnitude and frequency of 50Hz~16kHz. The results show that, the vibration amplitude of gun muzzle is μm magnitude. The measurement method has advantages of wide frequency response range, long measurement distance and high sensitivity. Vibration signal detection at long distance and wide frequency range is realized.