Abstract: Back-pressure test and single-point test have been extensively implemented the Gas feld of HD Sea Area. There is more than 20% of average error occurred when the open-flow capacity of a gas well was predicted by the empirical coeffcient of Chen Yuanqian or average empirical coeffcient obtained from gas wells that have back-pressure test data. In view of this, the authors tried to look for a method that can optimize the empirical coeffcient in the single-point method and minimize the error of open flow capacity calculated. Case study of X gas feld and Y gas feld show that the optimal empirical coeffcient are 0.083 and 0.15 respectively, and the average error of open flow potential are 4.3% and 15% respectively, which are 27.7% and 40% less than that of the conventional method, respectively. The study of this paper not only improves the accuracy of capacity evaluation by single-point method, but also can enhance the adaptability of single-point in the gas feld.