Mesoporous calcite with different architectures is successfully prepared via a facile microwave-assisted polyol process, followed by a calcination treatment. The precursor, obtained by microwave-assisted method in EG solvent without any other organic additives, is a composite of aragonite–calcium acetate hydrate. The morphology and contexture of the precursor could be easily adjusted by the different addition of urea. After calcination, the as-synthesized precursor can be transformed into pure calcite with intact morphology and architecture. The BET surface area and total pore volume are 22.70 m2/g and 0.044 cm3/g for the flower-like calcite, and 39.97 m2/g and 0.115 cm3/g for the hierarchically layered calcite, respectively.