Abstract: Through concluding the structure and characteristics of existing megnetorheological fluid dampers, a new type of magnetorheological fluid damper is proposed. The new one can be applied in the field of small size mechanical structure on the ground and the vibration isolation system in microgravity conditions. To verify the validity of the damper, there are six aspects discussed in the article, which are structure design, fluid design, magnetic circuit analysis, mechanical analysis, theoretic result and error analysis. It is found that it can be used when the damping force is small, and therefore, it widens the applied field of the magnetorheological fluid damper.