The invention discloses a weight sensor compensation method for a trolley container portal crane. The weight sensor compensation method comprises the following steps that the force bearing situation of an auxiliary steel wire rope is calculated according to output torque of an auxiliary motor on a trolley; the left-right adjusting position, the front-rear adjusting position and the tilting position of a trolley lifting appliance are calculated; the left-right adjusting position is calculated through the steps that the initial length of the steel wire rope is calculated, the theoretical lengthof the steel wire rope after the lifting appliance moves leftwards or rightwards is calculated, the rope length variation quantity of the steel wire rope is corrected, and component force of the steelwire rope in the vertical direction is calculated; the front-rear adjusting position is calculated through the steps that the initial length of the steel wire rope is calculated, the theoretical length of the steel wire rope after the lifting appliance moves forwards or backwards is calculated, the rope length variation quantity of the steel wire rope is corrected, and the component force of thesteel wire rope in the vertical direction is calculated; and the tilting position is calculated through the steps that the initial length of the steel wire rope is calculated, the theoretical length of the steel wire rope after the lifting appliance rotates clockwise by a certain angle is calculated, the rope length variation quantity of the steel wire rope is corrected, and the component force ofthe steel wire rope in the vertical direction is calculated.