Objective   To study the microstructure and biomechanical properties of freeze-dried iliac crest bone allograft with regard to its potential applications as bone substitute

scaffold for bone tissue engineering and in drug delivery system.    Methods   Procurement

processing

sterilization and conservation of the iliac crest allograft scaffold were all performed according to the guidelines of the American Association of Tissue Banks. The graft segments were impregnated with Fibrin glue and rifampicin using negative pressure technique. Its physical characteristics were observed including colour

texture and porosities.The pore diameter  and microstructure were investigated with scanning electron microscope．Its porosity and density were measured by liquid displacement. Biomechanical tests were conducted in axial compression

lateral bending and rotation modes.    Results   The freeze-dried iliac crest bone allograft was ivory white

clean and porous

presenting sandwich structure in tricortical and cancellous bone. The rifampicin crystal was cemented in the pore by fibrin. Its mean density

porosity and pore diameter was （0.35±0.03）g/ml

（67.23±9.12）%

（395.36±37.02）μm

respectively. The mean anti-rotation strength

compressive strength

elastic modulus

buckling strength was （5.96±1.53）

（9.94±0.73）

（376.14±27.32）

（15.70±2.35）MPa

respectively.    Conclusion   The freeze-dried iliac crest bone allograft is a natural porous bone substitute with satisfying biomechanical strength

showing a great potential for further exploration.