Abstract: To measure the vibration of micro-structure, a scheme of sensor basedon micro-optic-electro-mechanical system(MOEMS) with fiber-optic readout was proposed,and its mathematical model was deduced. The single-fiber readout structure and a micro-structure fixed in the front of the sensor were used. The micro-structure vibrated as the measured object moved, and its vibration caused the change of light intensity. The sensor detected vibration displacement by receiving the light intensity. As a result of the single-fiber structure and the parameters optimization of micro-structure, compared with other fiber readout structures, this system has the advantages of high sensitivity and miniaturization which is easier to match with fiber system. The response behaviors of the system to the piezoelectric ceramics excitation were studied through the experiments. And it could detect the vibration displacement of 0.18nm.