Underground regulating reservoir with overflow structure

The invention discloses an underground regulating tank with an overflow structure, which comprises a regulating tank cavern arranged below the earth surface and an overflow tunnel communicated with the regulating tank cavern, the overflow tunnel is fixedly connected to the upper half part of the regulating tank cavern and extends towards the direction deviating from the regulating tank cavern, and an overflow weir is arranged in the overflow tunnel. The structure of the underground adjusting tank is improved, the overflow tunnel is additionally arranged on the adjusting tank cavern of the underground adjusting tank and used for draining water from the adjusting tank cavern, and when the water inlet amount of the underground adjusting tank exceeds the highest water level limit of the adjusting tank cavern, the overflow tunnel can drain water from the adjusting tank cavern; excessive water can overflow into the overflow tunnel from the overflow dam and is discharged through the overflow tunnel; the overflow wei