Annular overflow drainage system of die-casting mould

The utility model discloses an annular overflow drainage system of a die-casting mould. The annular overflow drainage system of the die-casting mould comprises a die-casting mould insert, an annular slag discharging ladle, a slag discharging opening, a portion matched with a sliding block and a gas discharge slot. The slag discharging ladle is arranged on the tail portion of the mould insert, raw material slag of a die-casting mould and gas in a cavity are discharged into the annular slag discharging ladle through the slag discharging opening, and gas in the annular slag discharging ladle is discharged out of the die-casting mould cavity through the gas discharge slot. An annular slag ladle is adopted for a die-casting piece annular overflow drainage system, and slag discharging quantity is increased; the slag discharging opening is changed to a structure with a gradually increasing section area, the slag discharging opening assists in jacking out a product, and arrangement of a jacking bar on the appearance face of the product is avoided.