Abstract: Objective\ To observe whether the angiotensionⅡ（Ang\|Ⅱ） can affect the heme oxygenase\|1（HO 1） gene expression of aorta smooth muscle cell（SMC） in spontaneous hypertensive rats（SHR）. Methods\ 16 SHRs and WKYs were selected and divided into treatment group and control group, respectively. The treated group were feed with perindopril 2mg/kg/d through stomach intubation for 14 days, while control group were given the equivalent volume of normal saline. The HO\|ⅠmRNA expression in aorta smooth muscle cell and the concentration of Ang\|Ⅱ in plasma were measured by RT\|PCR and radioimmunoassay,respectively. Results\ In aorta SMC the expression of HO\|1 mRNA was negatively correlated with the plasma concentrations of Ang\|Ⅱ in treated group and control SHR groups,while no reationship between the two variables was found in WKY rats. Conclusion\ The increase of Ang\|Ⅱ inhibited the expression of HO\|ⅠmRNA of aorta smooth muscle cell in SHR. Perindopril may alleviate the inhibiting effect of Ang\|Ⅱ on HO\|l mRNA.