Abstract: In order to determine aquifer parameters and the distance between observation well and imaginary well from the observed drawdown data of both pumping and recovery stage of the test conducted in the aquifer with linear impermeable boundary,a new method is proposed.For deriving the useful formula,the first three terms in expansion series of the Theis' well functions for describing the changes of two stages of pumping and recovery are taken as simplified expresses of the well function respectively.With some suitable transformation,two linear equa-tions for two stages are established,and the constants in these two equations are composed of the parameters to be estimated,and the independent variables and dependent variables of these two linear equations are all the function of the observed data in test.Hence,as soon as the test data are transformed into the data of independent variables and dependent variables in these two linear equations,the linear constants may be calculated by the method of lin-ear regression method,and,then according to values of linear constants,the aquifer parameters and the distance between observation well and imaginary well can be estimated.Finally,an example is given to show in detail the application procedure of the proposed method.