The embodiment of the invention provides a data prefetching method of a DHT (Distributed Hash Table) memory system, a node and a system. The method comprises the following steps: a first memory node receives a reading request sent by a client side, a prefetching data block and a second memory node where the prefetching data block is positioned are defined according to the read data block and a set threshold of the predetching data block, and a prefetching request is sent to the second memory node, wherein the first memory node and the second memory node are identical or different nodes, the prefetching request comprises identification information of the prefetching data block, and the identification information is exclusively used for identifying the prefetching data block; and the secondmemory node reads the prefeching data block from a disk according to the prefetching request, and stores the prefetching data block to a local cache, so that the client side can read the prefetching data block from the local cache of the second memory node. By adopting the embodiment of the invention, the prefetching data block can be directly read from the cache, so that the data visit efficiency of each memory node in the system can be improved.