Turbidity measurement has important applications in water quality monitoring and other fields.Aiming at the problem of large-scale turbidity measurement,a turbidity measurement method based on equivalent minimum optical path is proposed.Using the 90 ° scattering method,the light intensity intercept is calculated by linear fitting of multiple groups of light paths and scattered light intensity measurements,and the mathematical relationship between the light intensity intercept and the turbidity to be measured is established.The light intensity intercept represents the equivalent scattered light intensity under the condition of minimum optical path,so as to reduce the influence of optical path under high turbidity,and ensure the high measurement accuracy in the low turbidity and high turbidity range.An experimental device for turbidity measurement with 13-path combination was built.The experimental results show that the maximum relative error of this method is 2.818% in the range of 250~2000 NTU.Compared with the direct measurement of scattering method,the average relative error is reduced by about 71%,which expands the measurement range of scattering method on the premise of ensuring the measurement accuracy.