A case of primary pulmonary arterial sarcoma (PPAS) treated with Endostar injection and radiotherapy and discuss the diagnosis, clinical characteristics, and pathology of PPAS. The patient complained of cough, sputum, fever, and chest pain with hemoptysis. Numerous nodules were seen in the computed tomography scan. The patient was diagnosed as pulmonary embolism (PE) by computed tomography pulmonary angiography. The pathology and immunohistochemistry results indicated soft tissue sarcomas, indicative of angiosarcoma. The nodules shrunk after 5 courses of endostatin and one course of radiotherapy, as seen by CT scan. Therefore, PPAS is clinically rare with nonspecific symptoms. Hence, it can be easily misdiagnosed as PE, biopsy for confirmation. Current treatment is limited and includes surgery. Hence, endostatin injection combined with other therapy may be an alternative treatment.