A magnesium-doped nano-hydroxyapatite/polyvinyl alcohol/chitosan (Mg-nHA/PVA/CS) composite hydrogel was developed and characterized for potential use in bone tissue engineering. The hydrogel was synthesized using a magnetic stirring-ion exchange method and repeated freeze-thaw physical cross-linking. The composite hydrogel was evaluated for its chemical structure, porosity, elemental composition, equilibrium swelling degree, moisture content, pH change, biomineralization potential, biocompatibility, osteogenic potential, and magnesium ion release rate. Scanning electron microscopy (SEM) analysis revealed a well-defined 3D spatial structure with micropores in the hydrogel. Fourier transform infrared (FTIR) analysis showed that the Mg-nHA/PVA/CS hydrogel promoted amide bond formation. Energy-dispersive X-ray spectroscopy (EDS) indicated that the hydrogel exhibited favorable biomineralization ability, with the 5% Mg-nHA/PVA/CS group showing optimal performance. The hydrogel displayed favorable water content, enhanced biocompatibility, and porosity similar to human cancellous bone, while maintaining an equilibrium swelling degree and releasing magnesium ions that created an alkaline environment. It also facilitated the proliferation of bone marrow mesenchymal stem cells (BMSCs) and their osteogenic differentiation. The Mg-nHA/PVA/CS hydrogel demonstrated significant potential for application in bone repair, making it an excellent composite material for bone tissue engineering. The hydrogel's physicochemical properties, including its porous structure and magnesium ion release, support its use in bone tissue engineering. However, further research is needed to fully understand the long-term effects of the hydrogel on bone tissue and to optimize its properties for clinical applications.A magnesium-doped nano-hydroxyapatite/polyvinyl alcohol/chitosan (Mg-nHA/PVA/CS) composite hydrogel was developed and characterized for potential use in bone tissue engineering. The hydrogel was synthesized using a magnetic stirring-ion exchange method and repeated freeze-thaw physical cross-linking. The composite hydrogel was evaluated for its chemical structure, porosity, elemental composition, equilibrium swelling degree, moisture content, pH change, biomineralization potential, biocompatibility, osteogenic potential, and magnesium ion release rate. Scanning electron microscopy (SEM) analysis revealed a well-defined 3D spatial structure with micropores in the hydrogel. Fourier transform infrared (FTIR) analysis showed that the Mg-nHA/PVA/CS hydrogel promoted amide bond formation. Energy-dispersive X-ray spectroscopy (EDS) indicated that the hydrogel exhibited favorable biomineralization ability, with the 5% Mg-nHA/PVA/CS group showing optimal performance. The hydrogel displayed favorable water content, enhanced biocompatibility, and porosity similar to human cancellous bone, while maintaining an equilibrium swelling degree and releasing magnesium ions that created an alkaline environment. It also facilitated the proliferation of bone marrow mesenchymal stem cells (BMSCs) and their osteogenic differentiation. The Mg-nHA/PVA/CS hydrogel demonstrated significant potential for application in bone repair, making it an excellent composite material for bone tissue engineering. The hydrogel's physicochemical properties, including its porous structure and magnesium ion release, support its use in bone tissue engineering. However, further research is needed to fully understand the long-term effects of the hydrogel on bone tissue and to optimize its properties for clinical applications.