Objective: The purpose of this study is to evaluate methods of primary repair of flexor tendon inzone Ⅱd morphologically and biomechanically.Materials and Methods: Twenty-four white Leghorn chickens were divided into 2 groups. The longtoes of each side were assigned for following procedures separately: (1) Group A: On the left side,the FDS and FDP tendons in zone Ⅱd were repaired after tendon transection. On the right side,only the FDP tendon was repaired. (2) Group B: The FDS and FDP tendons were transected with the epitenon and tendon gliding floor damaged. Tendon repair was the same as in group A. Six weeks later, tendon excursion, work of flexion of the toe and extent of.adhesion were evaluated.Results: In group A, there were no significant differences between the two experimental sides. In group B, excursion of the FDP tendon on the left side was less than that on the right side, and work of flexion of the toe and extent of adhesion on the left side were larger than that on the right side significantly (p＜0.05).Conclusions: This experiment demonstrated that the FDS and FDP tendons in zone Ⅱd should berepaired after they were transected, and when severe injuries of the tendons presented, the FDPtendon should be repaired with the FDS tendon partially resected.