Outbreaks of starfish (Asterias amurensis) pose a major threat to aquaculture and marine ecosystems in Qingdao, China, and no effective methods have been found to control them. A comprehensive study of collagen in starfish could be an alternative to high efficient utilization. Based on this, collagen was firstly extracted from QingdaoA. amurensis. Then, its protein pattern, amino acid composition, secondary structure, microstructure and thermal stability were investigated. The results showed that theA. amurensiscollagen (AAC) is a type I collagen composed of α1, α2, and β chains. Glycine, hydroxyproline, and alanine were the major amino acids. The melting temperature was 57.7 °C. From FTIR, UV spectra and CD chromatography, the AAC had an intact triple helix and secondary structure, and microstructural analysis showed that the AAC had a loose, fibrous porous structure. Next, the osteogenic differentiation effect of AAC on Mouse bone marrow stem cells (BMSCs) was investigated, and the results showed that AAC induced osteogenic differentiation of cells by promoting the proliferation of BMSCs, enhancing alkaline phosphatase (ALP) activity, promoting cell mineralization nodules and upregulating the expression of mRNA of relevant osteogenic genes. These results suggest that AAC might have the potential application to bone health-related functional foods.