The invention discloses a diamond recycling device. The device is characterized in that a gas-liquid mixed injection circulation device, a pressure control alarm device and a chlorine gas supply device are added to a reaction kettle, wherein the gas-liquid mixed injection circulation device comprises a pump, a frequency converter, a gas-liquid mixed injector and a pipe; the pressure control alarmdevice mainly comprises a buffer kettle, an alarm, a liquid level indicator pipe, a gas circulation valve and a pipe; the chlorine gas supply device comprises a metering scale which is arranged on oneside of the reaction kettle and used for placing a chlorine gas cylinder, a pipe which is connected with the upper part of the reaction kettle and provided with a chlorine gas valve and a chlorine gas distribution pipe. Chlorine gas can be dissolved in water to generate acid liquor to dissolve diamond waste while negative micro-pressure of the chlorine gas leakage is reduced, the condition that hydrochloric acid or nitric acid purchased in the original process entrains a large amount of water is avoided, so that water can be recycled in the production process and no waste water is discharged.