过氧化钙，化学式CaO₂。

白色无气味结晶性粉末，几乎无味道。极微溶于水，遇水分解放出氧气；不溶于乙醇、乙醚和丙酮。露置于湿空气中时能分解。与稀酸反应生成过氧化氢。八水物热至130 °C失去结晶水。为强氧化剂。属四方晶系结构，晶格常数 a = 6.197 Å, c = 10.967 Å，空间群 P4/mcc。

Calcium peroxide or Calcium dioxide (CaO₂) is a solid peroxide with a white or yellowish color. For all practical purposes calcium peroxide is insoluble in water but will dissolve in acid to form hydrogen peroxide. When in contact with water it will immediately begin to decompose releasing oxygen.