Wind speed is an important parameter for the operation of wind energy conversion systems (WECSs), and its obtaining affects the control of WECSs. A wind speed observation based on Newton-Raphson Method is presented, which uses the real-time states collected in the operation of WECS to estimate the tip speed ratio. Then the estimated can be calculated by the relationship of the tip speed ratio and the wind speed. Finally, the wind speed observer is respectively verified by simulation and the wind turbine simulator based experiment. According to the emulational and experimental results, the wind speed observer has a satisfactory performance, meeting the desired goals.