In this paper, we compare the cost of the structure due to change of weight of the structure according to change of annual power generation and height, calculated by changing wind speed of a 10kW horizontal small wind turbine, Optimum height of the wind turbine was considered. The cost of each model was calculated by changing height of the structure to 12 m, 24 m, 30 m, and 36 m. Wind speed was calculated by the Deacon formula, and annual power generation was calculated based on annual average wind speed at power generation height of each model. Then, economic efficiency was evaluated by comparing cost of the structure with total profit over the lifetime calculated by annual power generation, and a suitable model was selected based on evaluation. Computer analysis was conducted to evaluate structural stability of the selected model.