Taking the disk-type fiber optic accelerometer with a center-embedded and edge-fixed rigid mass block as an example, the stress and strain distribution on the flexural disk of the sensor is analyzed. The mathematical model for the acceleration sensitivity of the sensor is established based on Michelson interferometer principle, and the optimum sticking fiber disk dimension is discussed. Two sensors are fabricated and compared experimentally to verify the calculation model. With the above model, the sticking area and sensitivity calculating formulas are deduced under different boundary conditions. The result is useful for the design of disk-type fiber-optic sensors, such as accelerometer, pressure gauge and hydrophone.