The present invention discloses a power tool, a lawn mower, and a method for controlling a lawn mower. The lawn mower includes a blade, configured to cut grass; a chassis, configured to accommodate the blade; a front wheel connected to a front side of the chassis; a rear wheel connected to a rear side of the chassis; a motor at least configured to drive the rear wheel to rotate; a detection apparatus configured to detect a rotational speed of the front wheel; and a controller configured to enable the motor to decelerate when the rotational speed of the front wheel decreases, where the motor is connected to the rear wheel, and the detection apparatus is electrically connected to the controller. In the present lawn mower disclosed herein, a speed of a front wheel is detected to control a moving speed of the lawn mower, thereby enhancing the performance of the lawn mower and improving the user's experience. 90 o
