Human cytomegalovirus (HCMV) is a widespread opportunistic pathogen, causing chronic and persistent infections by controlling body’s immune system. During the long evolution process of the virus and the host, the virus has developed mechanisms to evade the host immune system. The viral genome encodes a large number of products to control the central functions of both innate and adaptive immunity of the host by inhibiting the functions of natural killer (NK) cells and dendritic cells, down－regulating the expressions of major histocompatibility complex (MHC) class I and II in infected cells, impairing IgG－mediated humoral immunity as well as regulating the functions of chemokines and cytokines. This paper reviews the immune interfering mechanisms by HCMV, and probes into the occurrence, development and outcomes of the interaction between the virus and the host.