A new method is put forward for analysis bending deflection of the wind-turbine steel tower based on transfer matrix method. The steel tower of wind-turbine structure is simplified as a beam-column with varying diameter involve in bending and torsion. The transfer matrix is obtained by solution of the differential equations of beam-column subject to an axial force and other complex loads in 2-dimension. One exist steel tower is analyzed by this method for example, and the on-plane deformation was calculated by the present method. The results show that transfer matrix method is reliability and accuracy, which can meet the requirement of wind turbine engineering structure, and it is effective to solve the problems of the wind-turbine tower, especially for the case with additional bending moments caused by compressive force.