Abstract: In order to improve the calculation methods for the prediction of product distribution from gravity separation, reduce computational process and achieve computer calculation conveniently,this paper outlines the basic process to estimate the distribution rate of gravity products by the Approximate Calculation Method. Moreover,the essence of dis- tribution rate and the morphological character of gravity distribution curve to gravity process were also investigated. Based on improved Logistic Curve Model,the distribution rate formula of dense-medium and jigging separation were deduced. Then the application example for distribution calculations corresponding to dense-medium and jigging separa- tion were given. Finally the quality and quantity index of the two methods were obtained. The calculations show that there is no appreciable difference between the two methods,this can be confirmed that the Direct Calculation Method and numerical results are correct and accurate. The conclusion of the research shows that the Direct Calculation Meth- od is simple and practical,the calculation results are not affected by the change of coal washability,and the theoretical foundation is reasonable, which can be a better alternative method as compared with the Approximate Calculation Method in the calculations of distribution rate.