Electrospun polycaprolactone/carboxymethyl chitosan (PCL/CMC) nanofibers treated by helium cold atmospheric plasma (CAP) and grafted with bone morphogenic protein-2 (BMP-2) were used scaffolds for the osteodifferentiation of stem cells to. For in vitro study, human bone marrow-derived mesenchymal stem cells (hMSCs) were cultured on these scaffolds, and their behaviors were assessed via optical microscopy, MTT assay, and SEM. The osteogenic differentiation of the hMSCs was evaluated by calcium content and alkaline phosphatase assays, Alizarin red and immunofluorescence (ICC) staining, and RT-PCR. The results showed that scaffolds not only can support the proliferation of hMSCs but also can promote their differentiation to osteoblasts without using any external osteogenic differential agent. The RT-PCR and ICC data revealed that the CAP treatment and BMP-2-functionalization have synergic enhancement on the ossification of hMSCs. These fabricated scaffolds can be used as promising candidates for bone tissue engineering applications.