Injectable　hydrogels　have　been　considered　as　promising　materials　for　bone　regeneration,　but　their　osteoinduction　and　mechanical　performance　are　yet　to　be　improved.　In　this　study,　a　novel　biocompatible　injectable　and　self-healing　nano　hybrid　hydrogel　was　on-demand　prepared　via　a　fast　(within　30　s)　and　easy　gelation　approach　by　reversible　Schiff　base　formed　between　-CH=O　of　oxidized　sodium　alginate　(OSA)　and　-NH2　of　glycol　chitosan　(GCS)　mixed　with　calcium　phosphate　nanoparticles　(CaP　NPs).　Its　raw　materials　can　be　ready　in　large　quantities　by　a　simple　synthesis　process.　The　mechanical　strength,　degradation　and　swelling　behavior　of　the　hydrogel　can　be　readily　controlled　by　simply　controlling　the　molar　ratio　of　=CH=O　and　-NH2.　This　hydrogel　exhibits　pH　responsiveness,　good　degradability　and　biocompatibility.　The　hydrogel　used　as　the　matrix　for　mesenchymal　stem　cells　can　significantly　induce　the　proliferation,　differentiation　and　osteoinduction　in　vitro.　These　results　showed　this　novel　hydrogel　is　an　ideal　candidate　for　applications　in　bone　tissue　regeneration　and　drug　delivery.　(C)　2021　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.　Published　by　Elsevier　B.V.　All　rights　reserved.