This paper tentatively proves with in vitro experiments that HCMV can infect almost all CT, EVT, ST, interstitial cells and villous interstitial substance inside villus in vitro; HCMV reproduces and proliferates in early pregnancy villus, arousing villous c-erbB-2, MMP-2 and MMP-9 protein expression level decrease, which may be one of the pathogenesis that HCMV infection causes the reduce of EVT invasion function, miscarriage, stillbirth, cerebellar malformation, fetus developmental retardation and other offspring abnormalities. The gene discussed is MMP9; the disease is cytomegalovirus infection.