The invention discloses a memory shared system and a device, as well as a method in a multi-core NUMA system. The system comprises a plurality of nodes; the operating system of each node comprises a memory shared device, the memory shared device comprises: a memory information collection and processing module, a memory application module, as well as a module establishing a distant end memory dynamic management structure and connected with a communication module. The method comprises the following steps: step S1, when the memory of a front node is deficient, the memory deficiency information is sent to other nodes, the node information of vacant memory in other nodes is collected, then the memory application information is sent to the nodes with vacant memory requesting the use of distant end memory; step S2, after receiving the memory application information, the nodes with vacant memory distributes the distant end memory with the current node, and let the current node dynamically manages and exclusively uses the distant end memory. The invention borrows the distant end vacant memory to accomplish the load leveling of the entire system.