Objective To study anatomic characteristics of the fibular collateral ligament (FCL) and its relationship with surrounding structures, and to explore its clinic significance. Methods We performed this anatomical study of the FCL and its surrounding structures using 61 formalin-fixed knees, observing and measuring its length, width, thickness, and relationship with surrounding structures. Results FCL consistently existed, it was on an average (61.41±6.21)mm in length, (4.14±0.74)mm in width, (1.96±0.37)mm in thickness. The angle between FCL and popliteal tendon was 41.8°±7.5°, the distances between FCL and fabellofibular ligament, popliteofibular ligament were (9.66±2.92)mm, (9.67±3.87)mm, respect