Objectives Study on the effect of ammonium bicarbonate solution on improving HIFU efficiency to ablate bovine liver in vitro. Methods After HIFU ablating bovine liver in vitro under different power levels, the datas of average gray-scale difference, gray-scale change area, and volume of coagulative necrosis between experimental groups with ammonium bicarbonate solution in different concentrations and PBS-injected control group are recorded and analyzed by statistical method. Results When HIFU ablation power is 150w, there are significant differences between experimental groups with ammonium bicarbonate solution in different concentrations and PBS control groups in average gray-scale difference, gray-scale change area, and volume of coagulative necrosis (P<0.05). However when with other power, the situation is not exactly the same. Conclusion When power is appropriate, ammonium bicarbonate solution can assist HIFU ablation of bovine liver in vitro.