The invention relates to a gravity abutment, in particular to a design method for increasing the limit height of a gravity abutment. The problem that a traditional gravity abutment is small in limit height is solved. The method includes the following steps of firstly, measuring the transverse bridge direction width of the gravity abutment, and if the transverse bridge direction width of the gravity abutment is smaller than a set threshold, pulling two side walls of the transverse bridge direction width of the gravity abutment towards each other through a plurality of prestress anchor ropes; secondly, measuring the gradient of the transverse bridge direction ground line of the gravity abutment, and if the gradient of the transverse bridge direction ground line of the gravity abutment is larger than the set threshold, anchoring the side walls of the gravity abutment and a mountain body together through a plurality of prestress anchor ropes; and thirdly, adding an unloading platform on the wall back face of a front wall of the gravity abutment. The method is suitable for designing the gravity abutment.