Abstract： Objective To investigate the postoperative 3D MRI appearances and their evolvement patterns of ACL grafts and bone tunnels at follow-up.Methods There were 26 double bundles ACL reconstructions and 16 single bundle ACL reconstructions,and a total of 56 follow-up 3D MR Imaging.MR images were reconstructed with MPR technique to evaluate grafts,bone tunnels,fixers and associated.complications.Proportions of grafts with hypointensity or hyperintensity and occurrence rates of marrow edema around bone tunnels were calculated respectively among groups of different periods after operation.Results There were 24 grafts of hypointensity and 32 grafts of hyperintensity.Grafts of 2 cases were suspended with cross pins within femoral tunnels,graft of 1 case was suspended with an endobutton within the femoral tunnel,and grafts of other sites were fixed with interference screws.In the three periods as 3 months,6 to 9 months and over 12 months after cruciate ligament reconstruction,proportions of hypointensive grafts were 20/25,0/14 and 4/10 respectively,while proportions of hyperintensive grafts were 5/25,14/14 and 6/10 respectively,occurrence proportions of marrow edema around bone tunnels were 54/54,10/32 and 4/26 respectively.There was 1 tear graft,4 tibial tunnels placed anteriorly with ACL graft impingement on the intercondylar roof,3 femoral tunnels placed anteriorly,and 2 bone tunnels with mismatching interference screws.Conclusion 3D MRI can accurately demonstrate the state of ACL grafts,bone tunnels,fixers and associated complications.Intensity of grafts presented a rise and reduce pattern after operation.