It is necessary to carry out reasonable deliverability study for a single well, since deliverability test of gas well in lowpermeability lithologic reservoirs is difficult and seldom and the capacity analysis data are little utilized. The sensitivities of characteristic parameters of single-point deliverability equation to permeability, effective thickness and skin coefficient are analyzed. The result shows that the common experience productivity formula is invalid for the gas reservoirs with different properties, complex boundary and strong heterogeneity. The modified isochronal test and the single-point method are integrated to determine the reasonable deliverability: the deliverability in Qigu Group in Niu 101-Ma 1 block is 1.5×10⁴m³/d, and it is 1.0×10⁴m³/d in Toutunhe Group.