In deep shale gas wells in Sichuan Basin, controlled pressure production mode is widely used, and there is no tested production rate of gas wells. Accurate understanding of production capacity faces challenges in the early stage. Therefore, based on theoretical analysis, a new capacity evaluation index is proposed, namely “apparent elastic yield”, which means the ratio of average daily production during stable production period to average daily pressure drop. Based on the statistical analysis of a large number of gas wells and considering the characteristics of the apparent elastic yield index, classification and evaluation process for gas well productivity is proposed, which includes “1st judgment, 2nd calculations, 3rd evaluations, and 4th classifications”, so as to achieve the classification description of high and low gas well productivity. Based on the calculation and statistics of the apparent elastic yield of different blocks, four characteristics of the rules are summarized. The application shows that the early productivity evaluation method for deep shale gas wells is scientific and effective.