Objective To explore the feasibility of pre-implantation of high-intensity suture into tendon grafts to prevent postoperative graft relaxation and creep in anterior cruciate ligament (ACL) reconstruction. Methods Thirty-six specimens of ACL reconstruction graft were made using adult swine’s Achilles tendon. All the specimens were randomly divided into experimental group (groups A and C) and control group (groups B and D), 9 specimens each group. One double-strand Ultrabraid No.2 high-intensity suture was pre-implanted into the grafts of groups A and C. Groups A and B underwent a 1 000-cycles load test while groups C and D underwent a 3 000-cycles load test. Then a pull-out test was performed until failure. The displacements at different cycles (100, 500, 1 000, 2 000, and 3 000) in all groups and yield loads of groups C and D were measured and analyzed. Results The displacement of group A was significantly smaller than that of group B at the cycles of 100, 500, and 1 000 (P<0.05); the displacement of group C was significantly smaller than that of group D at every cycle (P<0.05). Additionally, the yield load of group C was significantly higher than that of group D (t=4.816,P=0.001). Conclusion Pre-implantation of high-intensity suture into tendon grafts play an important role in the prevention of postoperative graft creep and relaxation in ACL reconstruction.