The invention discloses a device utilizing high-temperature flue gas with a high CO2 content to produce ultrafine active calcium powder and a production method thereof. The device comprises a carbonate burning kiln and a waste heat power generation boiler, and the carbonate burning kiln and the waste heat power generation boiler are connected through a pipeline. The waste heat power generation boiler comprises two outlets, one of the outlets is connected to an atomizing drying tower, the material outlet of the atomizing drying tower is connected to a grading and screening machine, the highly-damp waste gas outlet of the atomizing drying tower is connected to an anti-condensation dust collector, the outlet of the grading and screening machine is connected to the anti-condensation dust collector, the outlet of the anti-condensation dust collector is connected to a discharge chimney; the other outlet of the waste heat power generation boiler is connected to a wetting tower, the outlet of the wetting tower is connected to a high-temperature draught fan, the outlet of the high-temperature draught fan is connected to a dust collector through a raw material grinding and pulverizing device, the outlet of the dust collector is connected to an exhaust fan, and the outlet of exhaust fan is connected to the discharge chimney. The provided device can effectively absorb a large amount of carbon dioxide generated during the burning and production process of carbonate, processes and eliminates slag and waste liquid of slaked lime, and obtains ultrafine active calcium powder at the same time.