Abstract: It is difficult for conventional methods to evaluate dynamic reserves in fractured?vuggy carbonate reservoirs due to great differences in well performances. Accurate results cann’t be obtained with material balance method because more parameters are needed for calculation,which tends to bring some errors of them. After the driving stage is defined for reservoirs, the difference value of bottom?hole crude oil density obtained from two pressure tests and the cumulative production during the stage can be used to calculate the dynamic reserves more accurately. Compared with material balance equation and other methods, the method of bottom?hole crude oil density difference can avoid impacts of crude oil volume factor, crude oil compressibility coefficient and rock compressibility coefficient on calculation results,and the accuracy of calculated dynamic reserves can be further improved