The invention discloses a method for improving the underground continuous wall protecting mud recycling efficiency. The method includes the following steps of recycling waste mud from the interior of a groove of an underground continuous wall, separating large-particle waste soil in the waste mud by utilizing a whirling current separator, and obtaining low-specific-gravity mud; leading the low-specific-gravity mud into a high-speed revolution centrifugal machine, removing small-particle waste soil in the low-specific-gravity mud, and obtaining low-viscosity circulating mud; and adding newly-prepared mud into the low-viscosity circulating mud for regulation to obtain circulating mud with the qualified specific gravity index and viscosity index. The method for improving the underground continuous wall protecting mud recycling efficiency has the advantages that the method for improving the wall protecting mud recycling efficiency is simple, the mud waste rate of the underground continuous wall is decreased to 10% or below, the construction cost is reduced greatly, the construction speed is increased, and the construction quality of the underground continuous wall is ensured.