Objective: To assess the efficacy and safety of thrombolytic treatment with reteplase in patients with intermediate-risk acute pulmonary embolism. Methods: Ten consecutive patients with intermediate-risk acute pulmonary embolism who received thrombolytic treatment with reteplase at Thrombosis and Vascular Medicine Center, Fuwai Hospital from March to November in 2016 were included.Vital signs, right ventricular diameter, systolic pulmonary artery pressure, and biochemical markers were assessed before and after thrombolytic therapy with reteplase, and bleeding complications were also observed during 3 months follow up. Results: (1) For the efficacy outcomes: at 48 hours after thrombolytic treatment with reteplase, echocardiography-derived diameter of right ventricular was significant reduced from (27.9±3.8) mm to (24.8±2.6) mm (P=0.03), systolic pulmonary artery pressure decreased from (63.9±21.6) mmHg(1 mmHg=0.133 kPa) to (34.4±19.8) mmHg (P=0.02). Heart rate and breathing rate were also decreased significantly (both P<0.05), blood pressure remained unchanged post therapy.Hypoxemia was quickly corrected with an significant elevation of PaO₂ and SaO₂ ((65.2±14.3) mmHg vs. (80.0±9.6) mmHg, P=0.006; (90.8±3.5)% vs. (95.2 ±1.6)%, P=0.002 respectively). PaCO₂ was also increased significantly (P<0.05). Serum NT-proBNP and cTnI were decreased significantly (both P<0.05). There was no recurrent pulmonary embolism or deep-vein thrombosis during the 3 months follow-up. (2) For the safety outcomes: a thrombolytic relevant hemoptysis (about 70 ml) occurred in 1 patient, and was controlled by PCC therapy.No other clinically relevant events were observed during thrombolytic treatment. Eight patients were followed more than 3 months, there was no major bleeding complication or death during the follow up period. Conclusion Treatment of intermediate-risk acute pulmonary embolism with reteplase is effective and safe and there are no obvious side effects.