Aiming at the faults of seawater transparency empirical formulas having no universality based on the assumption of homogeneous water transparency, seawater is divided into several homogeneous layers with similar optical property in vertical direction, and non-uniform water contrast transfer equation is deduced.Based on the contrast transfer equation, the calculation model of seawater transparency is established.The calculation model is used to do numerical experiment and effect analysis using the inherent optical seawater data observed by BROKE_WEST_ACS and the data from transparency plate.Results show that the average relative error between the model calculation values in the paper and the observed values from transparency plate is 9.1%.The model not only overcomes the disadvantages of observations from transparency plate, which are easily influenced by weather conditions and human differences, but also breaks through the limitation of uniform water transparency calculation method.