【Abstract】 Objective To investigate the effects of simvastatin on the expression of TNF-α-induced TGF-β1 and CTGF in human peritoneal mesothelial cells (HPMCs). Methods HPMCs were isolated from human omenta by trypsin digestion method and cultured. HPMCs were then divided into normal control group, TNF-α-induced (1000ng/L) group and TNF-α-induced (1000ng/L) plus low-, medium- and high-dose simvastatin treated (2.5, 5 and 10μmol/L Simvastatin, respectively) groups. The viability of HPMCs was measured by MTT assay. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of TGF-β1 and CTGF mRNAs in HPMCs. TGF-β1 and CTGF in culture media were measured by enzyme linked immunosorbent assay (ELISA). Cell protein concentration was measured by trace bicinchoninic acid (BCA) method to correct the ELISA assay results. Results Low-, medium- and high-dose simvastatin significantly improved the viability of HPMCs inhibited by TNF-α (P＜0.05, P＜0.01). In addition, simvastatin significantly decreased TNF-α-induced TGF-β1 and CTGF expressions in a dose-dependent manner both at protein and mRNA levels (P＜0.05, P＜0.01). Conclusion Simvastatin inhibits the expression of TGF-β1 and CTGF in HPMCs cultured in inflammatory conditions.