An artificial knee joint includes a femoral component (1) and a tibial component (2). The femoral component (1) includes an intercondylar box (11). A cam (12) is provided on posterior of the intercondylar box (11). The tibial component (2) includes a medial condyle bearing surface (21) and a lateral condyle bearing surface (22) arranged on right and left side respectively. A post (23) is provided between the medial condyle bearing surface (21) and the lateral condyle bearing surface (22). The post (23) is adapted to the intercondylar box (11). The post (23) has a first arc surface (231) on the lateral side of posterior surface. The post (23) has a second arc surface (232) on the posterior surface and on the medial side of the first arc surface (231). A third arc surface (121) and a forth surface (122), cooperating with the first arc surface (231) and the second arc surface (232), are provided on the cam (12) accordingly. The first arc surface (231) can cooperate with the third arc surface (121) so as to guide the femur to rotate laterally with respect to the tibia. The second arc surface (232) can cooperate with the forth surface (122) so as to resist the femur to rotate laterally with respect to the tibia. The artificial knee joint can simulate accurately the flexion-extension action of the knee joint, and is safe and reliable.
