Abstract: Ca(NO₃)₂, (NH₄)₂HPO₄, acid dissolved collagen and gum Arabic were used as the raw materials to prepare collagen---hydroxyapatite/gum Arabic (ColHA/Gum A) composite in situ. The structures of the composite were investigated by XRD, SEM and FTIR. The mechanical properties, water absorption, enzyme degradation and cytotoxicity of the composite were investigated as well. The results show that the inorganic substance in the composite materials is hydroxyapatite, uniformly distributed in the ColGum A composite with relatively low crystallinity, and a new interface appeared by the interactions among them. The study on the mechanical properties, water absorption, enzyme degradation and cytotoxicity indicates a potential use in bone replacement for the new composite.