The invention provides a preparation method of cubic ultra-fine calcium carbonate particles. The method comprises the following steps: (1) adding a nucleation promoter to calcium hydroxide suspension liquid, wherein the nucleation promoter is selected from more than one of glucose, sucrose or sodium citrate; (2) carbonizing by introducing carbon dioxide until the pH value is 8-12, adding a crystal modifier and ageing for 0.5-10 hours, wherein the crystal modifier is selected from one of sodium chloride, sodium carbonate, sodium bicarbonate or sodium hydroxide; (3) further introducing carbon dioxide and carbonizing until the pH value is 6.5-7.0; (4) coating by adding a coating agent, filtering and drying to obtain a product, wherein the coating agent is selected from a resin acid, a resin acid alkali metal salt, a fatty acid or a fatty acid alkali metal salt. According to the calcium carbonate particles, the particle sizes are 90-180nm, the calcium carbonate particles are in a cubic shape, and the specific surface area is 10-18m<2>/g. Thus, the cubic ultra-fine calcium carbonate particles can be used as functional fillers in coating, rubber, plastic and sealant industries.