What is known and objective Intravenous to oral (IV-PO) antibiotic conversion, one of the critical elements in antimicrobial stewardship (AMS), is not well implemented in China. Studies on the strategy to apply the IV-PO conversion are needed. Our objective was to evaluate the impact and its barriers of a pharmacist-led practice with computerized reminders on IV-PO antibiotic conversion for community-acquired pneumonia (CAP) inpatients. Method This was a retrospective, observational pre- and post-intervention study. Interventions were introduced in 2 sequential 12-month phases: Phase 1: pharmacists implemented the conventional practice of reviewing patient charts and medication records every 24 h and verbally informed the prescribers on eligible IV-PO conversions; Phase 2: pharmacists implemented a new intervention practice to inform the prescribers with a computerized reminder in electronic medical record system on eligible IV-PO conversions. Main outcome measures The primary outcome was the proportion of patients who converted to oral therapy on the day patients were eligible for the conversion. The secondary outcomes were length of IV antibiotic therapy days, total length of antibiotic therapy days and length of hospital stay. Results A total of 524 patients were studied (256 in phase 1 and 268 in phase 2). The proportion of patients who converted to oral therapy on the day patients were eligible for the conversion was significantly increased from 34.77% (89/256) in phase 1 to 62.69% (168/268) in phase 2 (p < 0.05). Length of IV antibiotic therapy days in phase 2 was shortened by 1.23 days, which was 5.52 days compared to 6.75 days in phase 1 (p < 0.05). Total length of antibiotic therapy days was 12.05 days in Phase 1, compared to 10.75 days in phase 2 (p > 0.05). Length of hospital stay for patients in phase 2 was significantly shorter, with a difference of 1.38 days (6.02 days vs. 7.40 days, p < 0.05). The most common barrier of not converting IV-PO was the presence of co-morbidity. Conclusion The pharmacist-led IV-PO antibiotic conversion practice with computerized reminders was successful and feasible in Chinese hospitals. More IV-PO intervention studies in patients with other infections are needed in the future.