Objective To investigate the effects of human leukocyte-associated antigen-G (HLA-G) expression in silencing trophoblast cell line JEG-3 under normal and hypoxic conditions on invasion and proliferation of JEG-3 cells. Methods Inhibition of HLA-G expression in JEG-3 cells by transfection of small interfering RNA (siRNA),the transfected JEG-3 cells were divided into 4 groups: normoxia control group, hypoxia control group, normoxia inhibition group and hypoxia inhibition group. The levels of HLA-G mRNA and protein in 4 groups of cells were detected by real-time quantitive PCR and western blot. The proliferation activity and invasion ability of 4 groups of cells were determined by methylthiazolyl tetrazolium (MTT) assay and invasion assay.Results (1) Real-time quantitive PCR technology showed: the level of HLA-G mRNA in the hypoxic inhibition group (0.220±0.050) was significantly different (P<0.05), when compared with that in the hypoxic control group (0.630±0.030) and normoxic inhibition group (0.400± 0.020). (2) Western blot analysis showed: the expression level of HLA-G protein in the hypoxic inhibition group was 0.260±0.010, statistically different from that in the hypoxic control group (0.850±0.100) and the normoxic inhibition group (0.560±0.020; P<0.05).(3) MTT showed: proliferative activity of JEG-3 cells in the normoxic inhibition group was 0.490 ± 0.070, the ability of cell proliferation was reduced. When compared with that in the normoxic control group (0.850±0.050), the differences was statistically significant (P<0.05). The proliferative activity of JEG-3 cells in the hypoxic inhibition group (0.330±0.070) was lower than that in the normoxic inhibition group (0.490±0.070), and there was a significant difference (P<0.05). (4) Invasion assay showed: compared with the normoxic control group (98±7), the invasive ability of JEG-3 cells in the normoxic inhibition group (73 ± 7) was weakened, and the difference was statistically significant (P<0.05). The number of transmembrane cells (52±11) of JEG-3 cells in the hypoxic inhibition group was lower than that in the hypoxic control group (72±7), and the difference was statistically significant (P<0.05). Compared with the normoxic inhibition group, the invasion ability of JEG-3 cells in the hypoxic inhibition group decreased, and the difference was statistically significant (P<0.05). Conclusion Under hypoxia, using siRNA technology to down-regulate the expression of HLA-G may affect the proliferation and invasion ability of trophoblast cells, which may be involved in the occurrence of hypertensive disorder of pregnancy.