The invention provides a fiber grating-based GMA self-adaptive control method and device. A fiber grating sensor is adopted to acquire the mechanical coupling state information of multiple physical fields in a GMA actuation process in real time to obtain the feedback feature information of each component and extrinsic motivation of a GMA, and, based on the same, an online non-linear dynamic model of the GMA working process is established; the model self-adaptive follow-up control strategy between the motivation and the feedback is researched by analyzing the difference between anticipated feedback features and practical feedback features, so that the optimal self-adaptive control method meeting the application requirement is designed. According to the invention, the control to the GMA can be adjusted according to the change of working conditions of environments, and the GMA control accuracy can be guaranteed.