Calcium, as the most abundant mineral in human body, is involved in many physiological and pathological processes. Here, we reviewed the key mechanisms of calciumhomeostasis, includingcalcium sensing receptorregulation, intestinalcalcium absorption, renal calcium reabsorption andbone calciumresorption. We further discussed the roles ofdietary calciumandvitamin Din diseases associated with dysfunctional regulation of calcium. However, the over-dosed consumption of calcium could increase the risks for a series of diseases, such askidney stone,myocardial infarctionand stroke.Calcium, as the most abundant mineral in human body, is involved in many physiological and pathological processes. Here, we reviewed the key mechanisms of calciumhomeostasis, includingcalcium sensing receptorregulation, intestinalcalcium absorption, renal calcium reabsorption andbone calciumresorption. We further discussed the roles ofdietary calciumandvitamin Din diseases associated with dysfunctional regulation of calcium. However, the over-dosed consumption of calcium could increase the risks for a series of diseases, such askidney stone,myocardial infarctionand stroke.