Gas miscibility injection is one of the most effective ways to increase oil extraction. The Minimum miscibility pressure is an important parameter in the miscibility gas injection processes, which is very important for determining the type of injection gas and the design of injection facilities.1 In the industry, the minimum miscibility pressure is usually measured by slim tube, which is a relatively costly and time-consuming test, and may sometimes be counterproductive due to its specific problems, in spite of the high cost and time consuming costs. In this study, using the eclipse 300 simulator, the minimum miscibility pressure was calculated for 11 oil reservoirs with different injectable gases in the process of gas miscibility injection after simulation and compared with the experimental results of these 11 reservoirs and by calculating error percentage, the applicability of this method has been investigated.