In order to improve the working efficiency of the hydraulic wrench driven by the pump station and realize the automatic stop of the wrench,the corresponding relationship between the output oil pressure of the pump station,the displacement of the wrench piston and the torque of the bolt with time was analyzed.A method of judging and stopping hydraulic wrench based on PCA-SVM to identify the state of oil pressure was proposed.The characteristic parameters under different oil pressure states extracted by principal component analysis (PCA) were used as the input of support vector machine (SVM) to complete the accurate recognition of oil pressure state,and to indirectly realize the recognition of work state of pump station.By shortening the period of idle work in the pump station,the proportion of active work in the pressurization cycle was increased to improve the working efficiency of the wrench,and the automatic stop of the wrench was realized according to the corresponding relationship between oil pressure and bolt torque in the active work period.The experimental results show that this method can be used to improve the working efficiency of the pump station and realize the accurate stop of the wrench.