1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes containing CaCl2 were prepared in Tris solution. The optimal initial pH and temperature were determined based on the kinetics of bulk crystallization of CaCO3 and to depress the leakage of Ca2+ from liposomes. The CaCO3 particles were formed by mixing the liposome suspension and CO2-saturated water, as analyzed with the scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. The liposomal reaction system can be utilized for the formation of fine CaCO3 particles through sequestration of CO2.