Objective：To investigate antiatherosclerosis effect of atorvastatin in atherosclerosis model of SD rats，and to explore effect of nitric oxide in this course. Methods：Totally 60 male SD rats were divided into 4 groups randomly：control group，high-fat（HF） group，atorvastatin（ATV） group，and ATV+ N’-nitro-L-arginine-methyl ester hydrochloride（L-NAME） group. After being fed a high-fat diet，the rats were treated with ATV and ATV combined with L-NAME from 13 to 15 weeks，respectively. Pathologic changes of aortic arch were observed. Serum lipid level was determined. Furthermore，nitric oxide（NO），total nitric oxide synthase（T-NOS），endothelial nitric oxide synthase（eNOS） and eNOSmRNA were also determined. Results：The classical atherosclerotic lesions were fund in HF group and ATV+ L-NAME group，not in control group；serum lipid in the HF group was significantly altered（P<0.05）. Levels of serum NO，eNOS，vitality of serous T-NOS and mRNA levels of eNOS in the HF group were decreased（P<0.05）. Compared with those of HF group，atherosclerotic lesions were ameliorated in the ATV group. Serum lipid in the ATV group were significantly decreased（P<0.05）. Serum NO，eNOS，vitality of serous T-NOS and mRNA levels of eNOS in the ATV group were elevated（P<0.05）. Compared with those in ATV group，serum lipid levels in the ATV+ L-NAME group were significantly elevated（P<0.05）；serum NO，eNOS，and vitality of serous T-NOS in the ATV+L-NAME group were decreased（P<0.05）. Conclusion：Atorvastatin significantly enhances the activity of serum nitric oxide system. The blockage of nitric oxide pathway significantly bates antiatherosclerosis of atorvastatin.