The invention relates to a method for restraining generation of butter in an MTO (Methanol To Olefins) alkali wash system and mainly aims to solve the problem that the butter is more in the prior art. Through the method, a butter inhibitor is added into an MTO alkali wash tower; the inhibitor comprises an antioxygen, a polymerization inhibitor and a solvent, wherein the mass fractions of the antioxygen, the polymerization inhibitor and the solvent are 5-15%, 10-20% and 65-85% respectively; the antioxygen is SPEP; the polymerization inhibitor is hydroquinone. The technical scheme solves the problem in a better manner and can be used for restraining generation of butter in the MTO alkali wash system.