The invention relates to the field of orthopaedics medical appliance, especially an external functional knee joint fixing rack for early knee joint dirigation, which comprises locking pin structure composed of steel ball, C-formed tabular clamping steel ball rolling mechanism, C-formed tabular clamping steel ball slideway, U-formed head wedge steel ball support bar forming steel ball rolling slideway through vertically and horizontally matching, U-shaped rotating wheel comeandgo regulating and stabilizing mechanism, right locking pin mechanism, right adjustable arch form rack mechanism, eccentric shaft, left locking pin mechanism, and left adjustable arch form rack mechanism. The invention combines functional dissection of knee joint and biomechanics principle, is designed according to the traveling track of the unequal semidiameter center point of knee joint center of curvature, and has good stability and safety, good viability and flexibility for performing dirigation. The invention can be used for treating knee joint instability caused by ligamentous injury of knee joint, internal lateral ligament or ligamentum cruciatum anterius damage common in knee fracture, can effectively control crossrange activity of knee joint and promote ligament recovery.