The invention discloses a method for preparing an antibacterial tea scale detergent and belongs to the technical field of detergent preparation. The method comprises the following steps: extracting fructus kochiae medicinal liquid powder in an ultrasonic cleaning treatment mode, preparing chitosan powder from the powder and shrimp shells, compounding the chitosan powder with an alkyl amide propyldimethyl amino glycine betaine solution so as to obtain a surfactant compound, and grinding the compound into powder, thereby obtaining the low-toxin antibacterial tea scale detergent. Potato starch in the detergent is dispersed to form colloid, as a surfactant substance, alkyl amide propyl dimethyl amino glycine betaine, is adhered to the surface of the colloid to tear an oily membrane layer of tea scale, the fructus kochiae is rich in triterpenoid saponin and flavones compound which have relatively good inhibition functions on escherichia coli and staphylococcus aureus, then a good tanglingfunction is achieved in the colloid when the tea scale is cleaned by using the detergent, bacterial exposed after the tea scale is cleaned can be killed by various antibacterial substances in gel formed by the potato starch, and thus the purposes of sterilization and no emission of substances with toxic or side effect are achieved.