Abstract: To investigate the preparation and the biology security of the porous carboxymethyl chitosan/nano hydroxyapatite（CMCTS/n-HA）scaffold biocomposites，the porous biocomposites of CMCTS/n-HA were prepared by means of the porogen leaching method. In the process，anhydrous ethanol was the porogen leaching solvent and citric acid was the sticky solvent. CMCTS/n-HA were characterized by SEM, the porosity and compressive strength were also tested. At the same time，changes of the bone histology and the detecting function of liver and kidney were observed by implanting CMCTS/n-HA into the bone defects of rabbits. The porosity ratio of CMCTS/n-HA is about 75% and the compressive strength can exceed 21 MPa. The diameter of the pores is about from several microns to six hundred microns and most of them are circular, which  profits  the growth and extension of many tissues. The animal experiments show that  CMCTS/n-HA did not result in inflammatory reaction and bone putrescence and toxicity of liver and kidney. It is suggested that CMCTS/n-HA might be desirable for bone tissue engineering. So, CMCTS/n-HA would be a potential scaffold biocomposites for the treatment of bone defects.