The invention relates to a tobacco leaf topping machine. The tobacco leaf topping machine includes a traveling device; a topping support is arranged on the travelling device; topping blades are arranged on the topping support; the topping support includes a horizontal installation support which can be rotatably arranged on the travelling device through a support rotatable shaft; the topping blades are arrange on the horizontal installation support; the tobacco leaf topping machine also includes an inclination detection device which is used for detecting the inclination degree of the horizontal installation support while the horizontal installation support rotates around and inclines toward a central axis of the support rotatable shaft, and a horizontal adjustment mechanism which is used for driving the horizontal installation support to rotate around the central axis of the support rotatable shaft according to the detection result of the inclination detection device so as to allow the horizontal installation support to return to a horizontal position. The horizontal adjustment mechanism can drive the horizontal installation support to rotate around the central axis of the support rotatable shaft according to the detection result of the inclination detection device so as to allow the horizontal installation support to return to the horizontal position, and then the horizontal installation support can keep at the horizontal position while the travelling device inclines, inclination of the topping blades can be avoided, a flat topping effect can be ensured, and the topping effect can be improved.