Objective: To investigate the protective mechanism of spironolactone which pretreatmented in period of percataneous coronary interventional(PCI),by detecting the variation of mean arterial pressurein root of aorta（MAPA）, concentrations of aldosterone, Troponin I（cTn-I）, brain natriuretic peptide（BNP）and c-reaction protein(CRP). Methods: Patients who need to PCI in department of cardiology of Rugao people’s hospital from Junly,2007 to December,2010 were divided into two groups randomly, group of therapy (A group, n=116),group of contrast(B group, n=121).Spironolactone（20-40mg/d） was used in patients in group A ,and placebo was given to patients in group B. The levels of MAPA and the concentrations of Aldo,cTn-I,BNP ,CRP before and after PCI were detected or measured. All datas was analysed by software of SPSS11.5. Results: There were no significant different in age, sexual, operation time, times of balloon and number of stents between two groups. The concentrations of Aldo，cTn-I，BNP and CRP were all raised up in two groups after operation; there were no great difference in the concentration of the Aldo between two groups, but concentrations of cTn-I、CRP、BNP in group A were much lower than that in group B（P<0.05） and the level of MAPA was higher than that in group B. There were obvious dependablity between ΔMAPA(postoperative MAPA -preoperative MAPA)andΔcTn-I(postoperative cTn-I / preoperative cTn-I),ΔCRP(postoperative CRP/ preoperative CRP),ΔBNP(postoperative BNP/ preoperative BNP), and coefficient correlations were 0.61、0.38、0.59(P<0．05orP<0.01) Conclusion: Spironolactone could alleviate the injury of myocardial damage,and lessen inflammatory reaction in preoperative period of PCI. The possible pathomechanism might be related with that it could encourage the non-genomic effects of Aldo, and improve the perfusion of coronary.