A fiber Bragg gratings(FBG) flow sensor is designed and developed,which is based on cone shunt devices.And the fiber Bragg grating pressure sensor is used for signal demodulation.At the same time the switch is used to control different flow tube openings opening and closing situations.The sensor is very sensible to the flow velocity,and very stable.The measuring range is 92.5-802.3 mm/s,the sensor can detect the change of the flow velocity as low as 0.4 mm/s,and it is insensitive to temperature....