The invention discloses a method for improving soluble meal fiber content of lotus rhizome slag and belongs to the technical field of agricultural product processing. The method comprises 1, taking wet lotus rhizome slag, adding high temperature-resistant alpha-amylase into the lotus rhizome slag and carrying out enzyme treatment and filtering treatment, 2, adding a NaHCO3 solution into the wet material obtained through the step 1 and carrying out ultrasonic treatment, 3, adjusting pH of the mixture obtained through the step 2 to 5.0, 4, adding pectase and cellulase into the mixture obtained through the step 3 and carrying out enzymatic hydrolysis, 5, carrying out enzyme deactivation on the raw material slurry, 6, carrying out slurry separation on the raw material slurry obtained through the step 5 and 7, carrying out air flowing drying on the solids obtained through the step 6 to obtain lotus rhizome slag meal fiber powder. The method can improve soluble meal fiber content by 10% or more.