Objective To explore clinical characteristic of metal-on-metal hip joint prosthesis with large heads(ASRTMXL).Methods Total hip arthroplasty(THA)with ASRTMXL was performed in 14 patients including two with ankylosing spondylitis combined with hip amalgamation,three with avascular necrosis,two with secondary osteoarthritis and seven with femoral neck fractures.Based on shortterm follow-up results,we analyzed its design characteristic and clinical properties.Results All patients walked with crotches one week after operation and began weight bearing without support six weeks later.An improvement was seen on the average range of motion of the hip including anteflexion,retroextension,internal rotation,external rotation,adduction and abduction.The mean Harris score was increased from precperative 30 points(13-50 points)to postoperative 90 points(75-100 points),with statistical difference.Postoperative X-ray showed right positions of the prostheses,normal abduction angle and anteversion angle,without complications cccurred.Condusion Short-term follow-up results show that metal-on-metal hip joint prosthesis with large heads has advantages of lower wearing,large range of motion,few dislocation and small deformation of acetabular cup.