To evaluate the biomechanical action of lateral malleolar’s anatomical hook-plate in treatingWeber A-type ankle fracture. Methods Forty-eight cadaveric specimens of adult’s inferior extremities from June 2005to October 2006 were observed, consisting of 26 males and 22 females and aged 18-55 years. The external malleolus of the specimens were transected by using a wire saw at the ankle joint level, and then were divided into 4 groups randomly (groups A, B, C and D). Four distinct internal fixation instruments were used: lateral malleolar’s anatomical hook-plate in group A, general screws in group B , 1/3 tubular plate in group C and standard tension band in group D. Each group was further divided into 2 subgroups, A1-D1 and A2-D2. A1-D1 groups underwent anti-pressure and A2-D2 groups underwent anti-torsion biomechanically comparative analysis. Results The peak values of anti-pressure experiments in groups A1-D1 were (799.83 ± 105.47), (699.17 ± 63.81), (598.83 ± 123.14) and (453.00 ± 111.67) N respectively, group A1 was significantly higher than groups B1, C1 and D1 (P lt; 0.01); meanwhile, the peak values of anti-torsion experiments in groups A2-D2 were (37.17 ± 1.81), (30.33 ± 2.22), (20.50 ± 2.92), (24.83 ± 3.47) Nm respectively, group A2 was significantly higher than groups B2, C2 and D2 (P lt; 0.01). Conclusion The lateral malleolar’s anatomical hook-plate represents a definite biomechanical superiority, when compared with other 3 internal fixation instruments in treating fracture of external mlleolus.