Objective:To investigate the effect of different administration methods of recombinant human prourokinase (rhPro-UK) during emergency percutaneous coronary intervention (PCI) on myocardial perfusion and prognosis of patients with acute ST segment elevation myocardial infarction (STEMI).Methods:The clinical data of 132 patients with STEMI who underwent emergency PCI in the Military Hospital of the 71st Army Group of the Chinese People′s Liberation Army from August 2017 to August 2022 were analyzed retrospectively. Among them, 66 patients treated with rhPro-UK injection after the guide wire passed through the coronary artery lesion, balloon dilation and stent placement were included in group A. The other 66 patients treated with rhPro-UK injection once after the guide wire passed through the coronary artery lesion were included in group B. The two groups were compared in terms of PCI conditions, target vessel perfusion status [corrected TIMI frame count (CTFC) and blood flow (thrombolysis in myocardial infarction, TIMI) grade], myocardial perfusion status [TIMI myocardial perfusion grade (TMPG), ST segment regression rate (STR) at 90 min after operation and the incidence of no reflow/slow flow (NR/SF)], cardiac function indicators [left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV) and left ventricular ejection fraction (LVEF)], the incidence of major adverse cardiovascular events (MACE), and the incidence of bleeding events.Results:There were no statistically significant differences between the two groups in terms of the distribution of culprit blood vessels, intubation methods, and number of stents implanted ( P>0.05). After treatment, the proportion of TIMI blood flow grade 3 in the group A was higher than that in the group B:99.97% (64/66) vs. 87.88% (58/66). CTFC of the two tgroups decreased, and CTFC of group A was lower than that of group B: (23.49 ± 4.27) frames vs. (27.14 ± 4.83) frames ( P<0.05). The proportion of TMPG grade 3 in group A was significantly higher than that in group B: 95.45% (63/66) vs. 83.33% (55/66)( P<0.05). STR in group A was significantly higher than that in group B: 95.45% (63/66) vs. 83.33% (55/66)( P<0.05). The incidence of NR/SF in group A was lower than that in group B: 3.03% (2/66) vs. 14.29% (10/66)( P<0.05). There were no statistically significant differences in LVEDV or LVESV between the two groups before and after treatment ( P>0.05). After 1 month of treatment, LVEF of the two groups increased, and LVEF of group A was higher than that of group B: (71.08 ± 6.38) % vs. (66.24 ± 6.49) % ( P<0.05). After treatment, the incidence of MACE in group A was lower than that in group B: 6.06%(4/66) vs. 13.64%(9/66) ( χ2 = 2.13, P = 0.144). There was no statistically significant difference in the incidence of bleeding events between the two groups ( P>0.05). Conclusions:For patients with STEMI undergoing PCI, fractional injection of rhPro-UK can better improve myocardial perfusion, reduce the incidence of MACE, and effectively improve the prognosis, compared with one-time injection of rhPro-UK.