This paper introduces the working principle of laser high speed projectile measurement triggering device，analysis of the reliability of the trigger device for laser highspeed projectile measurement from three aspects ,the design of two lateral values of the transformer, the stability of the laser light source and the filter of the amplifier circuit. On the basis of the analysis，combined with the results of many experiments , points out the basic reason for the instability of the laser trigger device, and puts forward the corresponding solution. The final results are verified by experiments. The experimental results show that the corresponding adjusted laser trigger device can work stably and reliably, and can provide a stable and reliable trigger signal for other test equipment.