Objective To explore latest changes of joint proprioceptive function after posterior cruciate l igament (PCL) reconstruction using double-bundle semitendinosus and gracil is under arthroscope. Methods From June 2001 to November 2002, 25 patients with PCL ruptures were treated by arthroscope PCL reconstruction using double-bundle semitendinosus and gracil is, among whom 19 were males and 6 were females, aged 16-58 years old (36 on average). There were 6 cases of exercise injury, 15 of vehicle accident and 4 of fall ing injury. The duration before the operation was 1 week to 4 months (2.5 months on average). The posterior drawer test showed 23 patients were positive and 2 patients in the acute stagewere not cooperative. MRI indicated that all the patients had PCL injuries. The proprioceptive function of the knee joints was (4.73 ± 0.12)° before operation. Results All patients’ incisions obtained heal ing by first intention after the operation. The posterior drawer test showed that all the patients were negative. All 25 patients were followed up for 20-41 months (30.1 months on average). Eighteen months after operation, MRI indicated that bone marrow canal healed and internal fixation was stable. At the time of the last follow-up, the Lysholm score increased from (58.6 ± 15.2) before operation to (93.2 ± 7.4), and there was statistical difference (P lt; 0.05). The proprioceptive function of the knee joints was (5.67 ± 0.32)°, (5.45 ± 0.16)°, (3.80 ± 0.01)° and (3.67 ± 0.25)° at 5, 10, 15 and 20 months after operation, respectively. Statistical differences were observed between groups at 5, 10, 15, 20 months and the group before operation (P lt; 0.05). The proprioceptive function of the knee joints was (4.56 ± 0.11)° at the final follow-up, and was significantly different from that of the normal knee joints was (2.13 ± 0.41)°, (P lt; 0.05). Conclusion Joint proprioceptive function decreases temporally after the arthroscopy PCL reconstruction and begins to restore 15 months after operation, and improves sharply 20 months after operation. All patients’ Lysholm scores and symptoms improve after operation. Therefore, the operation is effective.