Abstract: Based on 30 groups of slim?tube experimental data of minimum miscibility pressure (MMP) in hydrocarbon gas?crude oil flooding system, including 8 groups of lean gas drive data and 22 groups of rich gas drive data, this paper makes regression and simulation of a new and universal empirical correlation expression for calculation of the hydrocarbon gas?crude oil flooding system MMP. This expression is a function about reservoir temperature, C7+ relative molecular mass of crude oil, volatile component in crude oil (CH4), intermediate components (CO2, H2S and C2-C6), the molar percentage and relative molecular mass of C2-C5, in injected gas, which can be used to universally calculate the MMP for dry gas and rich gas flooding. In this paper, the three empirical correlation expressions reported in the literature by Kuo, Firoozabadi?Azia and Pedrood that commonly used to calculate high precision of hydrocarbon gas?oil flooding system’s MMP are compared. The results show that the calculation results are more closed to the experimental data from the literature: the average of relative error’s absolute value is 6.11%, the maximum value is 16.39%. In order to further verify the new empirical expression’s prediction ability,other 6 groups of MMP slim?tube experimental data are applied, and the results are relatively high in accuracy, with the absolute value of relative error averages 1.94%, the maximum value is 4.10%