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  Magnetorheological fluid(MRF), which can provide continuously adjustable mechanical interaction for dynamical systems through solid-liquid morphology transformation under external magnetic fields, are of great interest for future applications in micro robots, automotive industry, precision machining and aerospace. With current material preparation methods, the particle sedimentation caused by inherent density difference between dispersed phase and carrier fluid limits the long-term stability of MRF, which has become a great obstacle to the promotion of MRF applications. Here we develop a strategy to achieve self-homogenization of MRF during MR rotary actuator’s working process by integrating a micro-surface structure with multiple oblique projecting lamellae on shaft’s surface. The sedimentation self-repair mechanism was analyzed via a coupling model of rotating shaft, magnetic particle and carrier fluid. The dynamic concentration changes of MRF during self homogenization were measured using a in-situ monitoring method based on the inductance sensing. The experimental results show that the MR rotary actuator with self homogenization function can resume normal operation within 60s after adding completely failed MRF, and the uniformity of MRF increased by 1800% compared to the initial failure state. We believe that this study establishes a route for the solution of MRF’s sedimentation, and is significant in improving the robust performance of MR rotary actuators and expanding the application boundaries of MR materials.