Abstract: Background　Methacrylated gelatin (GelMA) and its composites have been widely studied in the field of osteogenesis; however, research on hydrogels with reactive oxygen species (ROS) scavenging activity remains limited. Incorporating melanin nanoparticles (MNPs) with ROS-scavenging capability and β -tricalcium phosphate (β TCP) with osteogenic activity into GelMA could enhance the anti-ROS properties and osteogenic potential of hydrogel systems, thereby expanding their applications in bone tissue engineering.Objective　To synthesize a GelMA/β-TCP/MNP composite hydrogel and to investigate its biocompatibility, anti-ROS activity, biological properties, and osteogenic effects on MC3T3-E1 cells. Methods　Four types of hydrogels were prepared under 0.25% LAP (photoinitiator) and 405 nm light:GelMA, GelMA/β-TCP, GelMA/MNPs, and GelMA/β-TCP/MNPs, using 5% GelMA, 1% β -TCP, and 1 mg/mL MNPs. The microstructures of freeze-dried samples were characterized by SEM. Extracts from the four hydrogel groups were collected, with complete culture medium serving as a blank control. Biocompatibility was assessed using CCK-8 assay, live/dead staining, and TUNEL apoptosis assay; anti-ROS activity was evaluated with DCFH-DA staining; biological property regulation was determined via phalloidin staining, Ki-67 immunofluorescence, and scratch wound assay; and osteogenic potential was assessed by RUNX2 and OCN immunofluorescence staining.Results　(1) Freeze-dried GelMA/ β-TCP/MNP hydrogel exhibited a rough, three-dimensional porous structure with an average pore size of 103.6 μm, favorable for cell adhesion and proliferation. (2) Biocompatibility assays indicated no obvious cytotoxicity in any group. (3) Incorporation of MNPs into GelMA significantly enhanced intracellular ROS-scavenging activity. (4) Biological property evaluations showed increased cell adhesion (phalloidin staining), promoted cell migration (scratch assay), and enhanced cell proliferation (Ki-67) in the GelMA/β-TCP/MNP group. (5) Osteogenesis-related staining revealed that GelMA/β-TCP/MNP hydrogel exhibited the strongest osteoinductive ability compared with control and other material groups.Conclusion　GelMA/β-TCP/MNP hydrogel demonstrates excellent biocompatibility, effective ROS-scavenging activity, and enhanced cell adhesion, migration, and proliferation, while promoting osteogenic differentiation of MC3T3-E1 cells, indicating promising potential for bone tissue engineering applications.