As an effective treatment for acute ST-segment elevation myocardial infarction (STEMI), early reperfusion may reduce the infarct size and improve the prognosis of patients. However, it remains uncertain whether adjunctive thrombolytic therapy administered immediately prior to primary percutaneous coronary intervention (PCI) improves outcomes in patients undergoing the procedure within 120 minutes. In this investigator-initiated, prospective, multi-center, randomized, double-blind, placebo-controlled trial, subjects meeting the inclusion/exclusion criteria should be randomly assigned 1:1 to the trial group (r-SAK) or the control group (placebo). The risk of major adverse cardiovascular events within 90 days will be observed.