Abstract: Objective To investigate the effects of atorvastatin on the proliferation and collagen synthesis in cultured rat cardiac fibroblasts （CFs）. Methods CFs were enzymatically isolated from 12-week-old spontaneously hypertensive rats （SHR） and Wistar rats. Cell proliferation was evaluated by MTT assay and cell cycle distribution was determined with flow cytometer （FCM）. Collagen synthesis was measured by ELISA. Results （1） “A” values of CFs from SHR measured with MTT assay in the 10 -7 mol/L,10 -6 mol/L,10 -5 mol/L and 10 -4 mol/L atorvastatin groups were 0.30±0.01,0.26±0.01,0.24±0.01 and 0.22±0.01,respectively,which were all significantly lower than that of control group （0.33±0.01,all P ＜0.01）. “A” values of CFs from Wistar were 0.28±0.01,0.26±0.01,0.23±0.01 and 0.21±0.01,respectively,which were all remarkably lower than that of control group （0.30±0.01,all P ＜0.01）. （2） 10 -6 mol/L atorvastatin could increase the percentage of G₀/G₁ stage and decrease the percentage of S stage,G₂/M stage and proliferation index （PI）. （3） The contents of collagen Ⅰ secreted by CFs from SHR and Wistar rats in 10 -7 mol/L-10 -4 mol/L atorvastatin groups were significantly lower than those of control groups （all P ＜0.01）. Conclusion Atorvastatin dose-dependently inhibite the proliferation and collagen synthesis in cultured rat CFs. CFs from SHR were more sensitive to atorvastatin than those from Wistar rats.