Based on the installation requirements of a ice detector on airplanes， a three-dimensional numerical simulation method is used to simulate the airfield and droplet impact characteristic around the nose. Dangerous point is adopted to analyze the appropriate installation location of ice detector by demarcating the shadow area and increased concentration area of water droplet. Droplet collective characteristic and icing characteristic of ice detector are analyzed and compared with that of airplane’s main windward components. Results show that the maximum collection coefficient， icing intensity and icing degree of the probe surface are not lower than the corresponding characteristics of the main windward components of the aircraft， which meets the early warning requirements of ice detection.