A novel optical acceleration sensor based on a Fresnel diffractive micro lens is presented. It can effectively solve the low immunity of inertial sensors widely used in navigation system towards electro magnetic interference and electro magnetic pulse. A reflecting membrane is parallelly located behind the diffractive micro lens and its displacement is determined by the acceleration. Acceleration is calculated by measuring variational light intensity at the frontal focal point of the lens. The principles of the sensor and its dynamic system are described, and both the diffractive micro lens and the micro spring-mechanical structure of the dynamic system were designed and fabricated. Moreover, the performance and error of the sensor were analyzed. The results of proof-of-principle experiments indicate that the principle of the novel sensor is correct and the sensor has merits of simple structure and high sensitivity.