Objective To research the surface micro / nano-modification of porous calcium phosphate bone tissue engineering scaffolds. Methods Porous calcium phosphate bone tissue engineering scaffolds were prepared by the H₂ O₂ foaming method. Then the hydrothermal method was applied for the surface micro / nano-modification. The scanning electron microscopy ( SEM) was used for microstructure observations, and the X-ray diffraction ( XRD) was used to analyze the phase composition of the modified layer. Results After the surface modification, scaffolds with a total porosity of ( 63 ± 8 ) % , and a pore size of ( 310 ± 30 ) μm were obtained. The modified surface layers were hydroxyapatite nanocrystals or whiskers, the length of whisker ranged 20 ~ 40 μm, and the diameter was in range of 100 ~ 300 nm. Conclusion The inner and outer surfaces of porous calcium phosphate scaffolds formed a micro / nano-modification layer by hydrothermal treatment. The performance of the material was improved. KEY WORDS: