Abstract: Flow-induced tones will be generated in the case where the microphone mounted in high-speed flow.The SPL(Sound Pressure Lever) of flow-induced tones limits the required flow speed of aero-acoustic experiment.A nose cone,which plays an important role,must be jacketed the microphone for reducing flow-induced tones.In order to reduce SPL of flow-induced tones as much as possible,an experiment was conducted to investigate the characteristics of flow-induced tones of two different nose cones.The two nose cones,one is usual nose cone having a taper head and the other is one having hemisphere head with screen covered,were tested in NF-3 wind tunnel of North-Western Politechnical University,and the test section is octal with 2.2m wide every side.When the flow speed are 10m/s and 20m/s,the SPL and power-spectrum of flow-induced tones of the two nose cones are similar.When the speed reaches 30m/s、40m/s and 50m/s,their power-spectrum are still similar,but the nose cone with hemisphere head and screen,comparing with the usual one,can reduce the SPL of flow-induced tones by 3~11(dB).The results show that the nose cone with hemisphere head and screen is better than the usual one in aero-acoustic experiment when the sensor mounted in high-speed flow.