Calcification refers to the pathological process of abnormal deposition of calcium salts in body tissues, which includes two main categories:physiological calcification and ectopic calcification. The former is a normal physiological phenomenon, commonly observed in the development and maturation of teeth and bones; the latter, however, is a pathological condition where calcium salts deposit in non-osseous tissues, most typically affecting blood vessels and the myocardium. Clinical studies have shown that vascular calcification (VC) is closely related to osteoporosis (OP), and this mutually influential pathological phenomenon is referred to as the “calcification paradox”. Currently, the mechanisms underlying their coexistence have not been fully elucidated, but it is well-established that multiple common influencing factors exist, including disorders of calcium and phosphorus metabolism, chronic inflammatory responses, hormonal imbalances, and gut microbiota dysbiosis. Furthermore, VC and OP can regulate each other, promoting the occurrence and progression of both conditions. On the one hand, VC can lead to narrowing of the vascular lumen, thereby affecting blood perfusion in bone tissues and reducing bone matrix synthesis. On the other hand, various regulatory factors and matrix vesicles secreted by bone cells can not only regulate the process of bone mineralization but also promote VC by inducing the phenotypic transdifferentiation of vascular smooth muscle cells (VSMC) into osteoblast-like cells. In-depth research into the underlying molecular mechanisms of the “calcification paradox” holds promise for providing new insights and therapeutic targets for developing drug interventions that simultaneously improve bone and vascular health.