Objective To evaluate the effect of pressure load of avascular necrosis of the femoral head(ANFH) by percutaneous injection of polymethylmethacrylate(PMMA).Methods Models of ANFH were established in 20 adult white rabbits with 40 femoral heads which were induced by injection of hydrochloride(HCL) and hormone.DR was performed to observe the bony density of femoral head in all rabbits,the cystic degeneration and collapse of femoral head were detected in 21 femoral heads,then DSA was done to observe the blood supply and they were divided into three groups at random,group A in 5 was examined by pathology,group B in 8 was injected with PMMA and group C was as control.The test of pressure loading was performed in group B and C.Results Of 21 femoral heads with cystic degeneration and collaps,8 were in the HCL-induced group and 13 were in the hormone-induced group.DSA showed that the blood supply was decreased,and the arteria were decreased in diameter.After the percutaneous injection of PMMA,all of 8 rabbits in experimental group were successful.The distinction between the means of two samples was significant in loading test(P