Background Data regarding the influence of weekends and Chinese national holiday’s admission on the outcomes of patients with ST-elevated myocardial infarction (STEMI) is lacking. This study sought to investigate the effect of Chinese national holidays and weekend admission on outcomes in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI). Methods Patients presenting with STEMI within 12 h of symptom onset who underwent PPCI were retrospectively enrolled. The primary outcome of in-hospital mortality and major adverse cardiovascular events in patients presenting Chinese national holidays and weekends versus weekdays was evaluated. Results A total of 441 STEMI patients were enrolled in this study. Of these, 129 (29.3%) patients were admitted during Chinese national holidays and weekends and 312 (70.7%) during weekdays. Patients admitted during holidays and weekends were more likely to present with Killip class III-IV. Patients admitted during holidays and weekends experienced a significantly longer door-to-balloon time, symptom onset-to-door time as well as symptom onset-to-balloon time. The in-hospital mortality between patients presenting holidays and weekends versus weekdays was comparable. However, patients admitted during holidays and weekends have a significantly higher rate of in-hospital major adverse cardiovascular events. Multivariate analysis demonstrated that holidays and weekends admission was independently associated with adverse outcomes. Conclusions In China, STEMI patients undergoing PPCI during national holidays and weekends have worse in-hospital outcomes compared to those admitted during weekdays. These findings suggest that continuous efforts should be undertaken to enhance the Chinese healthcare system and to ensure that comparable outcomes are achieved for all STEMI patients regardless of time of presentation.