Objective To study the operative procedure and effect of arthroscopic reconstruction of both anterior cruciate l igament (ACL) and posterior cruciate l igament (PCL) with anterior tibial is tendon allograft. Methods From February 2005 to July 2006, 10 cases of both ACL and PCL rupture were reconstructed with anterior tibial is tendon allograft, including 7 men and 3 women, aging 18-45 years with an average of 30.2 years. The locations were left knee in 6 cases and right knee in 4 cases. All of them had identified trauma history. The disease course was about 1-3 weeks (mean 1.8 weeks). Both ACLand PCL were reconstructed under arthroscope with allograft anterior tibial is tendon of 26-28 cm in length and immobil ization with extention position brace was given for 4 weeks after operation. The active flex knee exercise was done from 0-90° at 4 weeks and more than 90° at 6 weeks. Results All operations were finished successfully, there were no blood vessel and nerve injury. The operative time was 90-110 minutes (mean 100 minutes). The wound healed by first intention and no early compl ication occurred. Ten cases were followed up for 12 months to 15 months with an average of 13.5 months. Thier gait was normal, knee activity degree was 0-135°. The anterior drawing tests and media and lateral stress tests were negative after operation in 10 cases; and the posterior drawing tests were negative in 8 cases and 2 cases was at grade I. Hydra arthrosis of knee occurred in 2 cases and was cured after remove of fluid and injection of sodium hyaluronate. The Lysholm knee function score was increases from 24.89 ± 5.39 before operation to 96.00 ± 4.59 at 12 months after operation, showing significant difference (P lt; 0.05). Conclusion Arthroscopic reconstruction of both ACL and PCL with anterior tibial is tendon allograft has the advantages of short operation time, less compl ications and good cl inical effects.