By means of temperature-controlled carbonization,heat-wet dyeing,heat-wet modification and dispersing treat-ment,the colorful nano-sized calcium carbonate products with good primary particle morphology were prepared on the plat-form of nano-sized calcium carbonate pilot plant.The laser granulometer test showed that the D₅₀ of colorful nano-sized calcium carbonate products was about 350 nm,with uniform particle size distribution and narrow distribution range.Products placed in the air for a long time without oxidation,color fading,indicating a good chemical stability.The hydrophilic test showed that the colorful nano-sized calcium carbonate products do not settle and lose color after being placed in water for a long time and stirred repeatedly,indicating that the dyeing and activation were stable.Taking acid mordant blue black B dye and stearic acid as examples,the mechanism of wet dyeing and wet activation of nano-sized calcium carbonate was analyzed,and the chemical crosslinking between the molecules of stearic acid,dye agent and calcium carbonate particles was discussed.