Maintaining appropriate mechanical strength and tissue volume is important to provide for sufficient alveolar bone growth. Recently, synthetic bone graft materials (BGM) including hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) have been widely studied for alveolar bone regeneration. Here, we applied gelatin-methacrylate (GelMA) hydrogel into the β-TCP to produce a GelMA/β-TCP composite (GelMA-B). This reinforced the mechanical strength and regulated the absorption period of β-TCP. To characterize the physical properties of the formed composite, GelMA-B was tested using a mechanical tester and a rheometer. It was then analyzed for biocompatibility and osteogenic differentiation using human adipose-derived stem cells. Further, the bone regeneration effects of GelMA-B were confirmed by an animal study. The cell viability analysis and qPCR results revealed that GelMA-B showed high cell viability and relatively high bone differentiation ability. In a rheological analysis, GelMA-B showed higher mechanical strength than β-TCP and GelMA alone. These features were confirmed in the animal study as GelMA-B maintained its volume and shape during regrowth, which can be favorable for alveolar bone regeneration. In addition to the regenerative effect, GelMA-B composite has an advantage for clinical use as the material enables structural molding for customized application.