Objective：To investigate the changes and clinical significance of intermediate mononuclear cells in preeclampsia in preg－nant women. Methods：Totally 64 preeclampsia women were selected as preeclampsia group. Sixty-four normal pregnant women of prenatal examination were taken as the control group. The pregnant women in the pre-eclampsia group were admitted to hospital. The blood samples of elbow vein were collected during antenatal examination of similar gestational weeks for flow cytometry and serum cytokine levels in healthy pregnant women. Results：Compared with those of control group，the proportion of intermediate and non-classical monocytes in preeclampsia pregnant women was significantly increased，and the proportion of classic monocytes was signifi－cantly decreased（P<0.01）. The percentage of intermediate monocytes in 29 cases of early preeclampsia was significantly lower than that in 35 cases of late preeclampsia（P<0.01）. The percentage of Toll like receptor（TLR）4，CD64 positive cells on the surface of in－termediate monocytes in preeclampsia group was significantly higher than that in control group（P<0.01）. In preeclampsia group，the average fluorescence intensity of triggering receptor expressed on myeloid cell-1（TREM-1）/TLR4 CD64 was significantly higher than that of control group（P<0.01）. The mean fluorescence intensity of tumor necrosis factor-α（TNF-α），interleukin（IL）-6 in interme－diate monocytes in preeclampsia group was significantly higher than that in control group（P<0.01）. The serum levels of TNF-α IL-6 and IL-8 in preeclampsia group were significantly higher than those in control group（P<0.01）. Mesenchymal monocytes and TNF-α in preeclampsia group（P<0.05）. There was no signifi－cant correlation between two projects in the control group. Conclusion：The proportion of intermediate monocytes in the peripheral blood of preeclampsia women is significantly increased，the expression of TREM-1，TLR4，CD64 on the surface of TREM-1，TLR4，CD64 are high，and the level of serum TNF-α/IL-6 is significantly increased，which may be involved in the process of preeclampsia in women with preeclampsia.