The invention relates to a robot zero point calibration method. The method comprises the steps that firstly, a first shaft is controlled to move in one direction with the preset speed, and the read number of a dial indicator arranged on the first shaft is obtained; secondly, when the read number of the dial indicator becomes small from large and then becomes large from small, the first shaft is controlled to stop moving, wherein one-time stroke of the first shaft is from movement starting to movement stopping; thirdly, the first shaft is controlled to reversely rotate and move in the opposite direction, and the difference value between the current read number and the previous read number of the dial indicator is calculated; fourthly, when the absolute value of the difference value is smaller than or equal to the preset deviation threshold value, the fifth step is executed, and when the absolute value of the difference value is larger than the preset deviation threshold value and the current read number of the dial indicator is larger than the previous read number, the first shaft is controlled to stop moving, and the third step is executed; and fifthly, the first shaft is controlled to stop moving, the current value of an encoder of a drive motor of the first shaft is recorded, and the current position of the first shaft is recorded as the mechanical zero point of the first shaft. By means of the robot zero point calibration method, the corresponding relation between the robot motor encoder value and zero point calibration shaft position is achieved.