The invention provides a carbonizing device for making nano calcium carbonate, which comprises a stainless steel tube, a micro-pore ceramic tube, a bracket with supporting legs, a sealing tube head assembly, an ultrasonic head and assorted ultrasonic power supply thereof, upper and lower coils, a cold water spray assembly, a pedestal and the like. The carbonizing technique FOR making nano calciumcarbonate by using the device and a carbonization method comprises the following steps of: charging CO2 gas into a cavity of the micro-pore ceramic tube from a CO2 input interface and filling Ca(OH)2latex emulsion in a liquid space from a Ca(OH)2 latex emulsion input interface. When air pressure maintaining the CO2 gas in the cavity of the micro-pore ceramic tube is higher than the pressure of the Ca(OH)2 latex emulsion in the liquid space, the CO2 gas will enter the Ca(OH)2 latex emulsion in the liquid space in a form of micro-bubbles via a plurality of micro-pores on a tube wall of the micro-pore ceramic tube to perform carbonization reaction with the Ca(OH)2 latex emulsion. The reaction is carried out under a condition that reverberation field ultrasonic wave energy environment causedby an ultrasonic head gets involved and the condition that the cold water spray assembly sprays cold water to maintain a reaction temperature.