The invention discloses a clinometer. The clinometer comprises a displacement sensor, a flexible rope or an elastic rod and a heavy object, wherein the heavy object is fixed at the bottom of the flexible rope or the elastic rod and located in the main body of the displacement sensor; a first reflection point is fixed in the main body of the displacement sensor or the joint of a radio frequency coaxial cable adapter and the shell and the inner rod is used as the first reflection point; one end surface of the heavy object is used as a second reflection point; the heavy object moves in the main body of the displacement sensor under the action of gravity to cause the second reflection point to move, so that the inclination angle is determined based on the variation of the relative distance between the first reflection point and the second reflection point; or, the displacement sensor comprises a positive feedback loop; if the positive feedback loop only comprises a reflection point formedby one end face of the heavy object, the weight moves in the main body of the displacement sensor under the action of gravity, the perimeter of the positive feedback loop is changed, and the inclination angle is determined based on the perimeter variation of the positive feedback loop.