A scheme of detecting multiplexed signal of fiber Bragg grating (FBG) sensor using cantilever beam tunable filtering technique is presented. The principle of the sensor is analyzed and the wavelength divided multiplex sensing property is demonstrated experimentally. The results of sensing measurement are accord with the resules measured with optical spectrum analyzer. The wavelength resolution of the sensor is mainly determined by the minimal detectable optical power of the system. The wavelength resolution of the measurement is 0.005 nm and strain resolution is 5.7×10-6, due to the high sensitivity photodetection system.