A method for detecting, controlling and automatically compensating pressure (F, F1, F2) in a polishing process, wherein it comprises the following steps: detecting a pressure (F, F1, F2) between a polishing wheel and a polished workpiece by a detection shaft or detecting a moment generated on the detection shaft by the pressure between the polishing wheel and the polished workpiece, and outputting the detected pressure (F, F1, F2) or moment (M, M1, M2, M3, M4) to a controller; comparing by the controller the pressure (F, F1, F2) or moment (M, M1, M2, M3, M4) detected by the detection shaft with a preset pressure or moment and determining whether there is a difference between them, and if there is not a difference, repeating the last step, or if there is a difference, carrying out a next step; calculating by the controller a compensation feeding amount based on the difference and outputting an adjustment signal to an adjustment shaft based on the compensation feeding amount; moving the adjustment shaft correspondingly based on the adjustment signal so as to drive the polishing wheel or the polished workpiece to move correspondingly to adjust a relative position between the polishing wheel and the polished workpiece so that the pressure (F, F1, F2) between the polishing wheel and the polished workpiece or the moment (M, M1, M2, M3, M4) generated on the detection shaft by the pressure between the polishing wheel and the polished workpiece tends to be and keeps consistent with the preset pressure or moment; and in the polishing process, continuously repeating the foregoing steps to keep the pressure (F, F1, F2) between the polishing wheel and the polished workpiece constant all the time, characterized in that the axis of rotation of the polishing wheel is horizontal and the center of the workpiece is on a same horizontal line with the center of the polishing wheel, the detection shaft is mounted along a direction that is parallel to the direction of the pressure (F, F1, F2) applied by the polishing wheel on the workpiece, and a sensor is mounted at an end of the detection shaft. detecting a pressure (F, F1, F2) between a polishing wheel and a polished workpiece by a detection shaft or detecting a moment generated on the detection shaft by the pressure between the polishing wheel and the polished workpiece, and outputting the detected pressure (F, F1, F2) or moment (M, M1, M2, M3, M4) to a controller; comparing by the controller the pressure (F, F1, F2) or moment (M, M1, M2, M3, M4) detected by the detection shaft with a preset pressure or moment and determining whether there is a difference between them, and if there is not a difference, repeating the last step, or if there is a difference, carrying out a next step; calculating by the controller a compensation feeding amount based on the difference and outputting an adjustment signal to an adjustment shaft based on the compensation feeding amount; moving the adjustment shaft correspondingly based on the adjustment signal so as to drive the polishing wheel or the polished workpiece to move correspondingly to adjust a relative position between the polishing wheel and the polished workpiece so that the pressure (F, F1, F2) between the polishing wheel and the polished workpiece or the moment (M, M1, M2, M3, M4) generated on the detection shaft by the pressure between the polishing wheel and the polished workpiece tends to be and keeps consistent with the preset pressure or moment; and in the polishing process, continuously repeating the foregoing steps to keep the pressure (F, F1, F2) between the polishing wheel and the polished workpiece constant all the time, characterized in that the axis of rotation of the polishing wheel is horizontal and the center of the workpiece is on a same horizontal line with the center of the polishing wheel, the detection shaft is mounted along a direction that is parallel to the direction of the pressure (F, F1, F2) applied by the polishing wheel on the workpiece, and a sensor is mounted at an end of the detection shaft.