The invention discloses a modification method of recombined phospholipase C. The modification method includes step 1, adding 2g of mPEG into a flask, adding 4mL of N, N-dimethylformamide, and allowing full dissolution; adding 0.12g of succinic anhydride, performing sealing and even mixing, stirring the mixture at the temperature of 100 DEG C while heating for 3 hours, adding 10mL of diethyl ether dropwise in a chromatography cabinet after reactors cool down, filtering out and drying sediments, re-dissolving the dried sediments by dichloromethane, and performing precipitation by diethyl ether; drying a sediment product, namely a modifying agent SS-mPEG, in vacuum, and storing the SS-mPEG in a drier for standby application; step 2, dissolving the SS-mPEG and the phospholipase C in a Tris-HC1 buffer solution according to a mole ratio of 0-30, allowing vibration reaction at the room temperature for a while, performing dialysis by a dialysis bag at the temperature of 4 DEG C, and cooling and drying obtained modified enzyme liquor for standby application, wherein the volume of the buffer solution is 10mL, the pH value of the buffer solution is 7.2 and the concentration of the buffer solution is 25mM. Modified enzymes obtained by the modification method have obviously higher heat stability, pH stability and catalytic efficiency as compared with original enzymes.