Abstract: Nano-sized calcium carbonate was synthesized by non-frozen gas blow mixing carbonation method.This  experi-ment  used calcium hydroxide suspension,which was produced by digesting and refining the lime produced in steel kiln of Chongqing Huanghua Calcium Carbonate Co.,and the kiln gas with volume fraction of carbon dioxide of 33%~35% as raw materials.This experiment also adopted self-developed sepcial blender and gas distributor and a certain amount of accessory ingredient in synthesis process.During the experiment,it was found that the problems of gas dispersion and mixing were solved well by self-developed blender and distributor.Research results showed that the preparation of nano-sized calcium carbonate with different particle sizes could be achieved within a certain range by controlling linear velocity of stirring and kiln gas flow.On this basis,the use of wet modification,through special self-developed  blender,adding a certain amount of modifier and using variable frequency control,the production of low-cost,high-grade nano-sized modified calcium carbonate could be achieved.