The invention discloses a load levelling method of an elevator mast, and relates to the levelling technology of elevating equipment platforms in the fields of radars, photoelectric sensors, microwave communication and the like. In the load levelling method, a side cantilever is adjusted to an angle which is consistent with an inclined direction of the elevator mast by adjusting an azimuth rotating shaft on the elevator mast, and then a pitching rotating shaft is adjusted, so that a vertical arm is vertical to the ground; and a load platform is mechanically vertical to the vertical arm, so that the load platform is adjusted to a horizontal or specified angle of elevation under the condition that the elevator mast inclines. The load levelling method has the advantages that a structure of the device is simple and easy to implement, the simple mechanism is adopted to realize the high levelling precision, a mast system adopting the mechanism is strong in stability and easy to lock, the requirement of mast strength can be reduced greatly under the condition of the same angle precision and the like. The load levelling method can be widely used for the levelling installation of fixed load elevating platforms, vehicle-mounted load elevating platforms and the like.