Unconventional oil and gas resources, especially shale gas resources have great potential for exploration and development in China. In Shale gas exploration and development process, reservoir pore pressure is a very important parameter, and the pore pressure prediction can improve the appraisal accuracy of project dessert. This paper analyzes several formation pore pressure calculation methods based on logging data, and optimized the “Equivalent depth method”. The preliminary results show that this method can carry out the accurate evaluation on the abnormal high pressure of the shale gas reservoirs of Fuling area with high calculation precision and application potential.