Objective　Through the study of the X-ray measurement of the anatomical parameters of 414 proximal femoral medullary cavity to provide evidence to the selection of geometric types and design of artificial femoral prosthesis.　Methods　Randomly select the X-ray DICOM data of proximal femoral pre-operatively of 414 cases which has undergone THA from March 2005 to December 2008 in First Affiliated Hospital of Suzhou University , measure 10 parameters of diameter and five morphologic parameters of the proximal femoral medullary cavity with DICOM VIIEWER software, and analyze the correlation among various parameters of proximal femoral and the correlation with gender and age.　Results　(1)There was significant positive correlation between the factor of age (female) with the internal diameter of isthmus. (2)MCFI mainly in 1.8～2.4), possessed 68.1% of all the test people. (3)According to Nobel'classification of proximal femoral medullary cavity, chimney-type (CFI<3.0) occupied 13.0%, the normal type (3.0<4.7) occupied 72.5%, funnel-shaped (CFI>4.7) occupied 14.5%. (4)MCFI and CFI showed strong positive correlation, but there was no significant correlation between MCFI and DCFI; CFI showed strong positive correlation with DCFI、and the opening angle of distal femoral ; CFI showed strong positive correlation with internal diameter of isthmus; DCFI had significant correlation with the opening angle of distal femoral medullary cavity.　Conclusion　(1)There was significant variation in the shape and size of proximal femoral medullary cavity,  and there was diference between Chinese and Caucasian to a certain degree. (2)MCFI( metaphyseal canal flare index) and CFI(canal flare index) and DCFI(distal canal flare index) had different emphases on describing the morphological characteristics of proximal femoral medullary cavity, and the three index combined with the parameters of diameter of proximal femoral medullary cavity could describe the shape of medullary cavity more accurately.