In order to realize acceleration measurement by fiber Bragg grating(FBG),a kind of two-spot fabrication FBG model based on elastic tube for acceleration sensing is proposed.First,the sensing principle of the model is analyzed theoretically,and the analytical formula of acceleration sensitivity is also established.By introducing the conception of ideal acceleration sensitivity,the response of acceleration sensitivity to frequency is analyzed and discussed.Second,the accelerometer based on the model is designed.The amplitude-frequency characteristics,resonance frequency and linear response of the FBG accelerometer are researched experimentally.Experimental results indicate that it has a good,flat and linear response at frequencies less than the resonance frequency:the linearity is 99.8%,the sensitivity is 63.0 pm/G,and the relative error is 0.98%.Analytical investigation agrees very well with experimental results.