1. An automatic calibration method for a robot system, comprising: calibrating a sensor and a sensor coordinate system of the sensor with respect to a world coordinate system; controlling a robot under the guidance of the sensor to move a point of a tool mounted on the robot to reach a same target point with a plurality of different poses, the point of the tool being in a tool coordinate system; and calculating a transformation matrix tcp T t of the tool coordinate system with respect to a tool center point coordinate system based on pose data of the robot at the same target point.