Single factor combined with uniform design were used to optimized the extraction process of protein from Momordica charantia residue by salt dissolving method, and the inhibitory activity in vitroon K562 cell proliferation of crude extract was determined by MTT assay. The test results showed that the optimal conditions were as followed: salt concentration of 0.25 mol/L, time 3.59 h, pH=9, ratio of liquid-material 10.36︰1 (mL/g) and the temperature of 25 ℃, extracting twice. Under this condition, the actual extraction rate was 9.28%. In the range of experimental concentration, the crude protein from Momordica charantia residue had a significant inhibitory effect on proliferation of K562 cells in vitro, and showed dose-effect relationship.