Objective To make further exploration of the structure characteristics of anterolateral ligament (ALL) and provide clinical reference for diagnosis and treatment of ALL injury, especially for ALL reconstruction through anatomical study of ALL in a Chinese population. Methods Sixteen cadaveric knees, including 8 left knees and 8 right knees with sex ratio of 1∶1 and a mean age of 73.5 years (range, 57-84 years), were dissected to reveal the ALL through a standard approach. A qualitative and a quantitative characterizations of the ALL were performed. Results ALL was seen in 75.0% of the specimens, originating on the lateral femoral epicondyle, proximal and posterior to the lateral collateral ligament (LCL). It coursed on LCL or was parallel to LCL, anterodistally to its anterolateral tibial attachment approximately midway between the center of the Gerdy’s tubercle and the lateral margin of the fibular head. A strong connection was observed between the middle part of the ALL and the periphery of the meniscal body of the lateral meniscus. The distance between the center of the insertion and Gerdy’s tubercle was (23.9±3.3) mm; and the distance between the center of the insertion and the lateral margin of the fibular head was (23.8±4.0) mm. The ALL length at 0° and 60° flexion and neutral knee rotation were (44.8±5.1) mm and (47.8±5.5) mm respectively (t=14.071, P=0.000), and the ligament had its great extend at 60° of knee flexion and internal rotation. Furthermore, the ALL length at 0° and 60° flexion of males were both significantly higher than those of females (t=2.920, P=0.015; t=2.806, P=0.019), while other measurements differences were significant between males and females (P>0.05). Conclusion ALL is an independent and a non-isometric ligament located in the anterolateral area to the knee, of which the length is different between males and females. ALL plays a role in rotational stability of the knee, and should be put much emphasis in clinical practice.