Laser screen velocity measurement system is widely used due to its real-time, non-contact, repeatability and high-precision measurement. This paper proposes a circular arc cylinder reflective laser screen velocity measuring method. The first step is to build and deduce the mathematical model of circular cylindrical reflective laser screen velocity measurement system, on this basis, the aberration formula of the optical system is calculated; and the mathematical expression of the theoretical light power density distribution in the effective laser screen area is obtained; optical simulation of the system is performed with Zemax, the photoelectric detection receives a narrow light spot with a diameter of 1.22mm , the result is similar to the theoretical aberration formula; the 7.62mm projectile is respectively passed through different areas of the light screen, calculating the difference value between that’s light power and the light power of the detector when no projectile passes through the light screen, obtaining the system signal sensitivity distribution, the results show that the light power density of the central superimposed region is higher than that of the two sides and decreases with the increase of the y coordinate, moreover, it jumps at the intersection of regions; the maximum variation of light power is 0.19mW , and the minimum is 9.9μW , the effective target surface utilization rate is 93.75% . The construction of the system provides a reliable basis for the design of velocity measurement target for large caliber projectile and another method for realizing velocity measurement of large range trajectory dispersion.