Previous study proved that it generated an in vitro model of macrophage-derived foam cell, namely, the characteristic pathological cell in the early atherosclerotic lesion to incubate C₅₇ BL/6J mouse peritoneal macrophages with 10 mg·L~(-1) oxidized low density lipoprotein for 4 days. With the Ca~(2+) fluorescent indicator technique and NADH-oxidizingcoupling-spectrum-analysis method, we determined the intracellular Ca~(2+)-ATPase of the above cultured foam-like cell. The results indicated that the [Ca~(2+)]i level was 2. 7 times higher than that of control group cells, and the activity of Ca~(2+)-ATPase was 24% of that of the later cells. This supported that macrophage-derived foam cell formation is connected with the slow Ca~(2+) entry or release, which possibly derived from long-lasting openings of membranous Ca~(2+) channels and the inactivating of Ca~(2+)-ATPase at the late stage.