Abstract: On the basis of analysis of several physical oil producing technique applied in Daqing Oilfield,this paper presents the technique of plug removal with hydraulic impact.This paper introduces the structure of hydraulic impact generator,the structure of the tubing string,the working principle and process;this paper also analyzes the surge pressure produced by the hydraulic impact generator,and presents the theoretical calculation formula used to estimate the surge pressure.Calculation results show that the generator can produce 20~40 MPa surge pressure which will not damage the casing and the tubing.Finally,this paper presents the field test results and several beneficial conclusions.