The present invention provides a data processing method, device and client in a distributed storage system. The client acquires a hash value of data according to characteristic information of the data, and determines at least two storage nodes corresponding to the hash value of the data according to a pre-established partition table and the hash value of the data. The at least two storage nodes correspond to different DHT overlay networks, so that the client can write the data to the at least two storage nodes. In a system, the at least two storage nodes only store one data copy, and the backup relationship is simple, so as to solve the problem in the prior art that, when one storage node joins or leaves the system, an affected storage node may comprise backup relationships of two sequential storage nodes in a clockwise direction and two sequential storage nodes in a counterclockwise direction of the affected storage node, because one storage node may store multiple different data copies due to complicated backup relationship of the storage nodes in the system, thereby reducing the difficulty in system maintenance and scheduling.