Abstract: The head recovery expression of a fully penetrated well in a confined aquifer and the step-head expres-sion of well flow in a confined aquifer can solve aquifer parameters on different discharge alteration.Both of water flow rate and pressure of water injection test on site are difficult to control and the accuracy is lower than that of head recovery curve.A head recovery expression of confined aquifer with step-pressure was deduced from step-head expression of well flow under principle of potential superposition.Based on field step-pressure injection test data the aquifer parameters are calculated and the feasibility of the expression is proved.