Abstract: Using phospholipid as the sole carbon source, Achromobacter sp. BIT-56 with a high-yield phospholipase was screened out from the oil-rich soil samples. Activity of the phospholipase produced by the best mutation strain could be improved by 73.3% through UV-induced mutation and 95.6% through UV-diethyl sulfate (DES) complex mutation as compared with the wild strain. When 100 U/kg of this phospholipase was added in the degumming of soybean oil and reacted at pH 5.0, 4% H₂O, and 40 ℃ for 4 h, 75.6% of the phospholipid of the soybean oil could be removed.