Abstract: Eggshell is an important source of biological calcium and used to prepare a variety of organic calcium as a dietary calcium supplements.It can be extensively used in a variety of industries.The formation of eggshell and calcite was contrasted. The common methods for preparing organic calcium from eggshell and the structural characterization methods were collected.The absorption and utilization of eggshell calcium in vivo was discussed.The research status of eggshell calcium was analyzed,and some further research directions about eggshell calcium were point out,which aimed to offer the scientific theory for the development and utilization of the eggshell calcium.