Abstract: Post-drilling evaluation is an important part of prospect evaluation in the oil and gas exploration processes. With the comparative analysis of pre-drilling prediction and post-drilling results, the experience is summarized, and the deficiencies in pre-drilling evaluation and prediction are corrected and improved, so that the pre-drilling evaluation and prediction results of exploration targets are more accurate, and the success rate for the coming oil and gas exploration can be improved. Based on introducing the main contents and methods of post-drilling evaluation, the problems and solutions that need to be focused on in post-drilling evaluation are summarized in this paper. By analyzing the geological risk factors and reserve parameters of both successful and failed drilling, the key elements of large deviation between pre-drilling prediction and post-drilling estimation are compared, and the causes for the deviation are discussed and improved, which can be helpful on improving the geological explorers' ability of prediction and enhancing the success ratio of exploration in the following work.