Capacity evaluation is the most important content for predicting gas well productivity, analyzing gas well dynamics, understanding gas layer and wellbore characteristics, and is of great significance for determining reasonable production countermeasures for gas wells. It is difficult and safe to use conventional monitoring techniques for abnormal high pressure gas reservoirs. The risk is large, and it is also affected by various factors such as technical conditions and wellbore conditions. It is impossible to put the pressure gauge into the bottom of the well. Based on the principle of capacity testing and evaluation, this paper summarizes the technology of gas well productivity evaluation and prediction based on the single well capacity data admission situation. The method can be used to meet the capacity evaluation and prediction under different conditions, and the results are reliable, and provide support for real-time evaluation of gas reservoir capacity and development of reasonable production.