In order to evaluate the water abundance of aquifer and solve the problem that the pumping pore size and the pumping water level drawdown are not unified in the unit water inflow of drilling hole, based on the measured data of pumping test, the drilling hole water inflow of 91 mm diameter is converted by using the diameter conversion formula. The Excel is used for data processing to draw the q=f( S ) curve, judge the type of curve. The relevant data of Q-S curve and the Q-S curve equation are determined by using the least square method, and the unit water inflow of 10 m drawdown is solved.In this study, the pore size of the pumping test is 108 mm, and the flow Qi is converted into the pumping hole flow with the 91 mm pore size by using the formula, and then the unit water inflow is converted. The conversion of unit water inflow bases on more than three pumping or discharging test data, the Q-S curve is drawn in the Q-S rectangular coordinate system. The results show that the method can intuitively judge the curve type, accurately determine the parameters and complete the conversion of unit water inflow.