Abstract: Response surface method was used to optimize the technological conditions of ultrasound-assisted extraction of pectin from lemon peel slag.Employ Box-Behnken experimental design, pH, extraction time and ratio of material/water as the running parameter, the yield of pectin as the response value.Experimental results showed that when pH value was 1.0, ratio of solvent to material was 20:1, extraction time was 50min, the extraction efficiency reached the maximum and the average extraction efficiency was 26.45% for 5 times of parallel experiments, which was in agreement with the calculated value.