Firelight or ambient light will bring an error trigger signal or can not capture the shot off target signal. These may affect accuracy and sensitivity of the system. It brings forward the overall design of the photoelectric velocity measurement system,the selection of laser diode power,and the design of the photo compensation circuit. Using the wavelength of 650nm PIN photodiode to form the large effective screen area,laser screen velocity measurement system comprised of lens hood,interference filter and special photoelectric conversion circuit measure execution of projectile. Then analyze the measurement system by simulation in laboratory. At the end,it is proved the usability of the suppression of ambient light and flames interference through the ball firing.