Abstract: Objective To investigate the changes in angiotensin Ⅱ type 1 receptor（AT₁ R）and type 2 receptor （AT₂ R）expression in platelets in patients of hypercholesterolcmia and the effects of atorvastatin.Methods Eight- y patients with hypercholesterolemia and sixty healthy persons were recruited.Atorvastatin（20 mg/d）were ad- ministed in hyperlipidemia patients for twelve weeks.The level of plasma angiotensin Ⅱ（Ang Ⅱ）was detected by the method of radioimmunoassay.The platelet expression of AT₁ R mRNA and protein were assessed by reverse transcription polymerse chain reaction（RT-PCR）and Western blot.Results Atorvastatin lowered cholesterol in hyperlipidemia patients（cholesterol,5.57±1.27 vs 7.08±1.23 mmol/L,P＜0.05）.①The plasma Ang Ⅱ of hy- perlipidemia patients was higher than that of controls（P＜0.01）but atorvastatin lowered plasma Ang lⅡ（P＜0.05）. ②The platelet AT₁ R mRNA and protein expression were also higher in hyperlipidemia patients than those of con- trols（All P＜0.01）,atorvastatin decreased the AT₁R mRNA and protein expression in platelets（AT₁R mRNA,0.93 ±0.22 vs 0.52±0.13;AT₁R protein expression,1.35±0.32 vs 0.72±0.16,P＜0.01）.③The expression of AT₂R mRNA and protein on platelets were also higher in hyperlipidemia patients than those of controls（P＜0.01）, atorvastatin increased both of them in platelet（AT₂R mRNA,0.85±0.16 vs after treatment:1.24±t0.28;AT₂R protein expression,0.81±0.17 vs after treatment:1.23±0.25,P＜0.01）.④The expression of platelet AT₁R and AT₂R protein were directly correlated with the level of plasma Ang Ⅱ（All,P＜0.01）in patients with hyper- cholesterolemia.Conclusion Atorvastatin downregulate the increased AT₁R mRNA and protein expression,but upregulate the increased AT₂R mRNA and protein expression in platelets in patients with hypercholesterolemia.