Objectives High-dose statins pretreatment is reasonable before percutaneous coronary intervention (PCI) to reduce the risk of periprocedural myocardial injury. However, the mechanism underlying this protective effect has not been elucidated. The aim of this study is to evaluate the effects of high-dose atorvastatin pretreatment on microvascular function and myocardial injury after elective PCI. Methods Eighty four patients underwent elective PCI were randomly assigned to high-dose atorvastatin (40 mg/d) and low-dose atorvastatin (20 mg/d) treatment for 7 days before PCI. The index of microcirculatory resistance (IMR) was measured by an intracoronary ressure/temperature sensor-tipped guidewire at maximal hyperemia after PCI. Fractional flow reserve (FFR) was measured before and after procedure. Troponin I levels were obtained at baseline and 20–24 h after procedure. Results IMR values were significantly lower in high-dose group when compared to low-dose group (16.5 ± 6.1 vs. 31.2 ± 16.0, P vs. 0.022 ± 0.04, P = 0.55). However, post-PCI troponin I levels in high-dose group were significantly lower than low-dose group (0.11 ± 0.02 vs. 0.16 ± 0.09, P 20 atm as an independent predictor of IMR > 32 (Odds ratio (OR): 3.3, 95% confidence intervals (95%CI): 1.3–8.5, P = 0.02). High-dose atorvastatin was the only independent protective factor of IMR > 32 (OR: 0.29, 95%CI: 0.11–0.74, P = 0.01). Conclusions The present study confirmed that diminishing microvascular impairment is one of the mechanism underlying protecting effect of high-dose statins pretreatment from myocardial injury during PCI. These suggest that high-dose statin pretreatment is reasonable in patients undergoing elective PCI.