The invention discloses a shield tail brush repair method which includes the steps: first, propelling a shield tunneling machine forwards to a stop position; second, stopping the machine and strengthening soil; third, detaching a duct piece: detaching the front-end duct piece and exposing a front-end shield tail brush; fourth, arranging an added shield tail brush: arranging the added shield tail brush on the inner side of the shield tail of the shield tunneling machine, and positioning the added shield tail brush in the front of the front-end shield tail brush and on the inner side of a duct piece ring detachment area; fifth, repairing the shield tail brush: repairing the exposed front-end shield tail brush to obtain a repaired front-end shield tail brush. A cavity between the added shieldtail brush and the repaired front-end shield tail brush is a grease cavity. The method is simple in steps, reasonable in design and good in use effect, shield tail sealing safety can be effectively improved by a tail brush repair mode combining the added shield tail brush and the repaired shield tail brush, and the risk of simultaneous replacement of two tail brushes can be avoided.