Objective To compare the clinical efficacy and safety of thrombolysis with anticoagulation therapy for patients with acute sub-massive pulmonary thromboembolism. Methods The clinical data of 84 patients with acute sub-massive pulmonary thromboembolism were analyzed retrospectively, mainly focusing on the in-hospital efficacy and safety of thrombolysis and/ or anticoagulation. The efficacy was evaluated based on 6 grades: cured, markedly improved, improved, not changed, deteriorated and died. Results Among the 84 patients,49 patients received thrombolysis and sequential anticoagulation therapy( thrombolysis group) , 35 patients received anticoagulation therapy alone( anticoagulation group) . As compared with the anticoagulation group, the thrombolysis group had higher effective rate( defined as patients who were cured, markedly improved or improved, 81. 6% versus 54. 3%, P = 0. 007) , lower critical event occurrence ( defined as clinical condition deteriorated or died, 2. 0% versus 14. 3% , P = 0. 032) . There was no significant difference in bleeding rates between the two groups ( thrombolysis group 20. 4% versus anticoagulation group 14. 3% , P gt; 0. 05) . No major bleeding or intracranial hemorrhage occurred in any of the patients. Conclusions Thrombolysis therapy may be more effective than anticoagulation therapy alone in patients with acute sub-massive pulmonary thromboembolism, and thus warrants further prospective randomized control study in large population.