Abstract: Taking the suspension being composed of nano-sized calcium carbonate，CaO，and dioctylphthalate（DOP） as the research objective，the rheological behaviors of calcium carbonate in coatings and sealants were simulated.The influences of the morphology，particle size，and surface property on rheological property were investigated.Results showed that the dispersion stability of suspensions prepared with different morphologies of calcium carbonate from strong to weak followed by：cubic，spindle，and chain.The thixotropic property and yield stress of suspension formed by cubic calcium carbonate were the best.When the average diameter increased，the size distribution narrowed，and the particle tacticity improved of the nano-sized calcium carbonate，the thixotropic property and yield stress of the suspension were enhanced.With the increase of the amount of coating agent，the thixotropic property gradually increased，whereas the amount of coating agent exceeded 3% （mass fraction），the thixotropic property was negative.

Key words: nano-sized calcium carbonate, rheological property, surface property, crystal shape, particle size