Abstract: In order to prepare hybrid nanostructure composite with magnetocaloric effect, combining with the superior characteristics of chitosan (CS) and collagen (Col) as the organic matrix, the soluble calcium salt and soluble phosphate as the precursor of inorganic phase nano hydroxyapatite (nHAP), and the soluble salt and soluble ferrous salt as precursor to inorganic phase superparamagnetic nano Fe₃O₄ particles were used to prepare Fe₃O₄-CS-Col-nHAP composite scaffold by in situ fabrication and freeze-drying technique. The composition and morphology of Fe₃O₄-CS-Col-nHAP composite scaffold and the distribution of nano particles were characterized by FTIR spectroscopy, XRD and SEM. And the magnetic energy of the scaffold was tested by physical property tester (PPMS). The results show that Fe₃O₄-CS-Col-nHAP composite scaffold presents a homogeneously interconnected macroporous structure which has an everage size of around 100-150 μm and the porosity is about 95%. And the low crystallinity of nHAP crystals and nano Fe₃O₄ particles are uniformly distributed in the organic matrix. The nano Fe₃O₄ particles prepared by in situ fabrication has super paramagnetic properties, with the increase of magnetic nano particles, the magnetic saturation strength is enhanced. The saturation magnetization intensionsity of Fe₃O₄-CS-Col-nHAP composite scaffold is about 0.025 emu/g. Therefore, the hybrid nanostructure Fe₃O₄-CS-Col-nHAP composite scaffold prepared by in situ fabrication and freeze-drying technique has good magnetocaloric effect, and is promising for bone repair application in bone tissue engineering.