Abstract: This paper proposes the detection principle of optical fiber sensing ice thickness on wind turbine blades surface and designs a four-channel ice detector with double windows. The distribution of droplet collection rate under different attack angles and droplet sizes is calculated and analyzed by using simulation software platform. The ice detector on the top of its nacelle and three wind turbine blades approximately have the same airflow field to realize the ice thickness measuring and its distribution estimation of three wind turbine blades. The real icing experiment and thickness measuring demonstrated on a wind turbine. The results show that the ice thickness at the leading edge of the blade is maximal and increases gradually along the tip direction. and the difference between the ice detected values and the actual values is within 8%,which can satisfy the application requirements of the ant icing and deicing engineering application on wind turbine blades.