Aim To investigate the effect of early application of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor on inflammation level and microcirculation function after PCI in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Methods From December 2019 to December 1,0 patients with NSTE-ACS who underwent PCI in the People's Hospital of Henan University of Chinese Medicine were selected and randomly divided into control group (55 cases) and PCSK9 inhibitor group (55 cases) according to the random number table method. Patients in control group was treated with atorvastatin calcium tablets, and patients in PCSK9 inhibitor group was treated with evolumab on the basis of the control group. After 6 months of treatment, the blood lipids, inflammation levels, coronary microcirculation resistance index and differences in coronary TIMI myocardial perfusion grade (TMPG) were compared. Results Compared with control group, the levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDLC) and lipoprotein(a) in PCSK9 inhibitor group were significantly decreased after treatment, and the differences were statistically significant (P＜0.05). The levels of high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were significantly decreased after treatment, and the differences were statistically significant (P＜0.05). After treatment, the index of microcirculatory resistance (IMR) of PCSK9 inhibitor group was lower than that of control group, and the difference was statistically significant (P＜0.05). Six months after surgery, TMPG level 3 in PCSK9 inhibitor group was higher than that in control group, the difference was statistically significant (P＜0.05). Conclusion Early application of PCSK9 inhibitor on the basis of statins can improve inflammation level and microcirculation function after PCI in patients with NSTE-ACS, which is worthy of clinical promotion.