The explosive growth of information to promote the development and evolution of the network storage system structure, object-storage system came into being, the object-based storage system stores the data in a storage device with intelligent in Object-based Storage Device, and the use of the metadata server to manage the metadata, but when the metadata access amount is very large, there is a potential performance bottleneck exist in MDS, so metadata server load balancing is very important, this paper studies the metadata server load balancing technology, proposed a dynamic equilibrium strategy based on permissions.