1. A node controller, applied to a multiprocessor system comprising at least one node controller (NC) and at least one processor connected to the NC, wherein the NC comprises: at least one pseudo cache agent (PCA) conforming to a processor micro-architecture level interconnect protocol and embedded in the NC, wherein the PCA is connected to at least one PCA storage device which stores data shared among memories in the multiprocessor system, and the PCA comprises: a data obtaining module, configured to, if the NC receives a data request, obtain target data required in the data request from the PCA storage device connected to the PCA; and a sending module, configured to send the target data obtained by the data obtaining module to a sender of the data request.