Abstract： Objective To compare the diagnostic value of magnetic resonance imaging (MRI),computed tomography (CT) and radiography in the early detection of arthropathies of haemophilia.Methods Prospective studies of 21 joints in 11 patients were studied with X-ray,CT and MR examination. The 21 joints with haemophilia arthropathies were divided into three groups according to Pettersson scoring system.0 point were the first group,＜4 points were the second group,≥4 points were the third group.Abnormal imaging findings of osteoporosis,enlarge epiphysis,erosion of cartilage,irregular subchondral surface,narrowing of joints space,joint deformity,subchondral cyst formation,effusion/haemarthrosis of joint,synovial hypertrophy with haemosiderin,deformity of joints were used for all imaging comparison.The results were analysis with Chi-square test.To compare the first group,irregular subchondral surface and the number of subchondral cyst formation of all symptomatic joints were detected by CT and MR,the results were analysis with pair-sample t test.Results Moderate and severe hemophilic joints were found in 80.95％ (17/21)of twenty-one symptomatic joints,and mild hemophilic joints were found in 19.05％ (4/21).The detected results were the same in enlarge epiphysis,narrowing of joints space,joint deformity in all joints by radiography,CT and MR.Significant difference in detection of irregular subchondral surface,subchondral cyst formation,effusion/haemarthrosis of joint,were found between radiography with either CT (x2 value 19.06,16.70,4.84,P ＜0.05 ) or MRI (x2 value 19.06,16.70,7.76,P ＜0.05),Significant difference in detection of the first group joint irregular subchondral surface and the subchondral cyst formation total number were found between CT and MR ( x2 =3.29,P ＜ 0.05 ). Conclusions MR and CT were superior in detection of the early abnormal changes in evaluating hemophilic arthropathies,however CT could detect more smaller irregular subchondral surface and subchondral cyst formation than MR.