Objective：This study aims to investigate the related factors and prognosis of peripheral blood leukocyte（PBL）in elderly patients with acute pulmonary thromboembolism（APTE）. Methods：Total 326 elderly patients over 60 years old that were hospitalized and diagnosed APTE in the First Affiliated Hospital of Nanjing Medical University from January 2016 to June 2019 were enrolled. Patients were divided into elevated PBL group（n=78）and normal PBL group（n=248）. Logistic regression was used to analyze the factors associated to PBL elevation in elderly APTE patients，including the age，gender，D-dimer level，pulmonary embolism site，proximal deep vein thrombosis（DVT），distal DVT，basic diseases，deep venous catheterization，smoking history and glucocorticoid application. Results：The PBL in the group with proximal-distal lower extremity DVT was significantly higher than those in the group without DVT and the group with distal lower extremity DVT only（P < 0.05）. Statistical analysis and logistic regression analysis showed that heart failure，recent（< 30 days）fracture，interstitial lung disease，and D-dimer levels were associated factors of elevated PBL in elderly patients with APTE（P < 0.05）. The incidence of adverse events（including mortality in hospital，use of vasoactive drugs，use of mechanical ventilation，cardiopulmonary resuscitation，etc.）in the elevated PBL group was higher than that in the normal PBL group（P < 0.05）. Conclusion：The prognosis of elderly APTE patients with elevated PBL was worse. We need to pay more attention to elderly APTE patients with cardiac and pulmonary insufficiency and DVT in proximal-distal lower extremity.