Objective To investigate the relationship between the anterior cruciate ligament (ACL) single-bundle anatomical reconstruction femoral tunnel and the lateral collateral ligament(LCL) reconstruction femoral tunnel, in order to provide the anatomical data for ACL and LCL one-stage reconstruction and to avoid mutual interference between the two femoral tunnels. Methods Thirty adult cadaveric knees without degeneration, deformity and joint damage were utilized. The cutting ends of each specimen were at least 20cm above and below the knee. The cadavers were 16 males and 14 females, aged from 23 to 66 years, 38.7 years for average. The femoral tunnel was drilled through an accessory medial portal (AMP) at 120°of knee flexion. The posteriolateral corner ligament (PLC) in the outer surface of lateral femoral condyle was visualized and the LCL was isolated and the LCL tunnel was drilled. All the specimens were underwent CT scan to observe the tunnel collisions on CT slices, and calculate the shortest distance between two tunnels. Results The shortest distance between the LCL reconstruction femoral tunnel and the ACL reconstruction femoral tunnel was (3.90±2.40)mm when the depth of LCL tunnel was 25mm. The shortest distance between the LCL tunnel and the ACL tunnel was (2.70±1.90)mm when the LCL tunnel depth was 30mm. The shortest distance between the LCL tunnel and the ACL tunnel was (4.4±2.60)mm when the ACL tunnel depth was 25mm. The shortest distance between the LCL tunnel and the ACL tunnel was (3.2±2.10)mm when the ACL tunnel depth was 30mm. Among 30 specimens, 6 cases were found tunnel collisions, the collision probability as high as 20%. Conclusion The risk of tunnel collisions between the reconstruction femoral LCL and ACL tunnels is high. Thus, when the one-stage of clinical anatomical reconstruction, preoperative preparation should be individualized, and the length and diameter of the femoral tunnel for reconstruction LCL should be planned to avoid collision with the ACL femoral tunnel.