A Double-semicircle Cantilever Beam(DSCB) accelerometer based on a fiber Bragg grating (FBG) was proposed to measure the acceleration signals. Firstly, the model of FBG accelerometer based on the two-dot coating was established, and the linear response between acceleration and displacements of sensitive elements was analyzed theoretically. Then, the natural vibration of the FBG based two-dot coating was described, and the effects of the length and prestress of the coated fiber on natural vibration frequency were discussed. Finally, according to the natural vibration of FBG, the FBG accelerometer was designed, and the linear response, amplitude-frequency characteristics, and direction anti-interference of the FBG accelerometer were researched experimentally. Experimental results indicate that the sensor has good flat response from 10-250 Hz, and the sensitivity of the accelerometer is 41.2 pm/G. Furthermore, the sensor can offer a good linear response in a linear fitting of 99.8% and a good cross-axis anti-interference ability in the cross-axis sensitivity less than 4.8%.