The acousto optic Q switch is used in the laser cavity as an acousto optic modulation Q device.In the pulse operating mode,the first pulse laser has so considerable power that the acousto optic crystal can be destroyed or make the laser mark too deep.The conventional first pulse suppressive (FPS) technology uses two external imput signals of the modulation signal and the burst signal to supress the first pulse power,thus the operation is rather complex and easy to cause error.A novel first pulse auto suppression method has been presented in this work.The proposed FPS technology uses MCU and CPLD to change the width of the previous pulses automatically,thus the light pulse intensity of the previous pulses can be suppressed automatically.