The basic optical properties of the optical microfiber coupler are discussed. Optical microfiber couplers with well optical property are achieved by using the optical microfiber drawing system with online optical monitoring system. The vibration characteristics of the optical microfiber coupler are analyzed and studied experimentally. Person stepping signals are caught successfully by the optical microfiber coupler sensing system, which proves that the optical microfiber coupler sensing system has high sensitivity to the vibration signal and it may have potential value in the local area monitoring fields.