In a method for preparing cerium carbonate powder by mixing a cerium precursor solution with a carbonate precursor solution and carrying out a precipitation reaction, wherein cerium carbonate is controlled to have an orthorhombic crystal structure, a hexagonal crystal structure or an orthorhombic/hexagonal mixed crystal structure, by using at least one type of organic solvent comprising at least two hydroxyl groups (OH) in molecular formula as a solvent for either or both the cerium precursor solution and the carbonate precursor solution, and varying a number of carbons or hydroxyl groups (OH) included in the molecular formula of the organic solvent. The method can easily and inexpensively obtain cerium carbonate powder with a desired crystal structure without the danger by high-temperature high-pressure and the need for an expensive system in hydrothermal synthesis.