Acute Pulmonary Embolism (PE) is a common disease in middle and high altitude areas. This study aimed to investigate the diagnostic value of plasma microRNA-134 for acute PE. Acute and chronic PE patients and healthy controls were recruited from March 2014 to July 2017 in Xining (2260 m, middle altitude) and Yushu (3600 m, high altitude) in China, with 20 subjects in each group (n=20). Plasma miRNA-134 levels were determined by real-time quantitative PCR with Taqman probes. The diagnostic value of miRNA-134 for acute PE was evaluated using the Receiver Operating Characteristic (ROC) curve. In both middle and high altitude areas, plasma miRNA-134 levels were the highest in patients with acute PE, followed by patients with chronic PE and healthy controls. In addition, plasma miRNA-134 levels were significantly higher in acute and chronic PE patients and healthy controls in high altitude area than in their counterparts in middle altitude area, respectively. Compared with Ddimer, miRNA-134 had a lower sensitivity but a higher specificity for the diagnosis of PA. Plasma miRNA-134 can be a promising diagnostic biomarker for acute PE patients in middle and high altitude areas.