The rapid detection of particle size distribution of suspended particles in water can be realized by static light scattering method based on CMOS detector. However, the measurement range and accuracy of particle size based on forward light scattering method were difficult to improve, which was limited by the working characteristics of the CMOS detector and the size of the screen. Therefore, a multi CMOS measurement technology for particle forward light scattering was proposed, focusing on the splicing measurement method of dual CMOS scattering signals, and a CMOS detector ring-splitting method to eliminate background interference was designed to achieve accurate measurement of particle size in a wide particle size range. The results show that the upper limit of particle size measurement based on CMOS detector is increased to 1000μm, and the relative error of D50 measurement of 1000μm and 500μm standard samples is 0.7% and 0.1% respectively, and the measurement accuracy of large particle size particle size is high; The method of double CMOS detection increases the particle size measurement limit of single CMOS from 5μm to 2μm. the relative error of D50 of 5μm and 2μm standard samples decreased from 15.0% and 51.1% of single CMOS to 1.4% and 2.6% of double CMOS respectively.