Three kinds of turbines (Vestas V-47:660 kW, Enercon E−40:600 kW, Vestas V-66:1.75 MW) were installed on three selected sites (Mailiao, Jhongtun, Chunfong) as wind power plants for electricity generation on an island. However, such power plants including turbines in establishment and operation during entire life cycle are bound to consume energy and produce carbon emission, causing environmental problems. Therefore, the purpose of the present study is to evaluate the effects of three wind power plants on the environment during their entire life cycle. This paper made the calculations of carbon emissions of three wind power plants, and compared and discussed the occupied shares of each primary energy input in manufacture, construction, operation and disposal phases using the methods of mathematics and materials input-output life cycle assessment. The results show that the CO2 emission factor of three systems was on average 3.9 g/kWh for the whole life cycle. The average CO2 emission intensity of all raw materials was 1.35 kg/kg. The occupied share of CO2 emissions in manufacturing, construction, and decommissioning phases was 44%, 16%, and 40% respectively. The primary energy input intensity was on average 0.0625 MJ/kWh of three systems for whole life cycle. The average energy input intensity of three systems was 21.48 MJ/kg. The combined CO2 emission intensity of all steel materials was 1.98 kg/kg. The demands for materials and energy inputs, and carbon emissions are positively related to the rated power value of a wind turbine. Wind power has a priority to produce clean energy, and can significantly decrease CO2 emissions.