The utility model relates to a battery repair instrument which comprises a microcontroller, an AC/DC switching circuit, a DC/DC switching circuit, a charging/discharging control circuit, a load and a discharge circuit, wherein the output of the AC/DC switching circuit comprises two paths, one of which is connected with the DC/DC switching circuit, and the other one thereof is connected with a rechargeable battery; an output end of the DC/DC switching circuit is connected with the microcontroller and the charging/discharging control circuit, and is used for supplying power for the microcontroller and the charging/discharging control circuit; a control output end of the microcontroller is connected with a control input end of the charging/discharging control circuit; a control output end of the charging/discharging control circuit is connected with the AC/DC switching circuit, and is used for controlling the output of the path of the AC/DC switching circuit connected with the rechargeable battery; the discharge circuit is connected with the rechargeable battery, and the load is connected with the discharge circuit; and a control end of the discharge circuit is connected with the control output end of the charging/discharging control circuit. By adopting the technical scheme, the battery repair instrument greatly improves the battery repair quality, and leads the recovery capacity of the battery to reach 60%-70% from the original 50%.