Distributed file system is an important part of the cloud platform, a number of uncertain factors may lead the file system unbalanced, which directly affects the performance of the cloud platform. So this paper proposed a dynamic load-balance algorithm of distributed file system in the cloud platform. The algorithm obtained the local node-information by the gossip protocol, allocated file workload by the node capacity and physical position information, and gradually realized load-balancing. Compared to Distributed, Centralized load-balancing algorithms, this algorithm has better performance in moving cost, message overhead and load transform cost.