Objective　To study the relationship between syncytiotrophoblast microvillous membrane (STBM) shedding in severe preeclampsia (sPE) and placenta Rho/ROCK molecule expression. Methods　In this study, placenta tissue of 20 sPE lying-in women (sPE group) and 20 normal lying-in women (control group) were collected. The syncytiotrophoblast microvillous structure of the placenta tissue was scrutinized with transmission electron microscope (TEM). The microvillous numerical density (Nv), surface density (Sv), and volume density (Vv) of the cell surfaces were analyzed with stereology method. Western blotting and immunohistochemistry were used to detect the expression of Rho subfamily proteins (RhoA, RhoB, RhoC) and Rho kinases (ROCKI, ROCKII) in the placenta tissues. The correlation of the expression of Rho, ROCK proteins, and the shedding of STBM was examined with Spearman rank correlation analysis. Results　The Nv, Sv, and Vv of the syncytiotrophoblast microvillous membranes in sPE group were significantly less than those of the control group (P < 0.05). Compared with the control group, the expression levels of RhoA, RhoB, ROCKI, and ROCKII proteins in sPE group were noticeably elevated (P < 0.05). In sPE group, the expressions of RhoB, ROCKI, and ROCKII proteins were positively correlated with the shedding of STBM (r=0.631, r=0.826, r=0.865, P < 0.05). Conclusion　The signaling pathways constituted by RhoB and its downstream molecules ROCKI/ROCKII, may play an important regulatory role in the upregulation of STBM shedding in sPE.