Abstract： Objective To investigate the diagnosis and treatment of pulmonary embolism(PE)in hospitals of different medical levels and further explore the diagnostic strategy for PE in primary hospitals.Method The clinical data from twenty hospitals of different medical levels in 8 provisions of China were retrospectively investigated using stratified cluster random sampling method and questionnaire form during may 2001 to may 2008.The questionnaire included:the general situation,the underlying diseases and triggering factors(risk factors),clinical manifestations,examination findings,rate of misdiagnosis and correct diagnosis,treatment and prognosis.Inclusion criteria:age≥18 years,passed pulmonary angiography or enhanced CT to confirm the diagnosis of PE.The data was input the Epidata database.Comparison of the rate of count data used chi-square test.Results(1)A total of 302 collected from 20 hospitals including 11 tertiary hospitals(n = 204)and 9 second hospitals(n = 98).(2)Of 12 risk factors,deep vein thrombosis and surgical operation accounted for 23.4%,16.2%,respectively.Of 22 clinical manifestations,the incidences of chest tightness,dyspena,palpitations,chest pain,shortness of breath and tachycardia accounted for over 40%in all.Laboratory examinations showed the percentage of blood Ddimer over 500 μg/L was 74.6%and the percentages of serum enzyme and creatine kinase isoenzyme were 50.1%and 0%,respectively,on ECG,the incidence of sinus tachycardia,low or inverted T waves of V1 to V6 leads,ST segment depression,complete or incomplete right bundle branch block and typical SⅠ QⅢ TⅢ were 55.4%,35.7%,27.2%,26.9%and 25.9%,respectively.On chest X-ray,the incidence of increase in lung markings,the shadow of the lungs,pleural effusion,prominent pulmonary artery segment,right pulmonary artery widened,regional lung atelectasis and pulmonary blood vessels sparse were 46.4%,36.1%,24.2%,24.2%,17.5%,9.3%,and 7.7%,respectively.The echocardiography showed the incidence of pulmonary hypertension,right ventricular dilation,lower right ventricular wall motion and pulmonary artery thrombosis were 66.7%,50.7%,16.4%and 6.8%,respectively.(3)The misdiagnosis was made in 55(18.2%)of 66 patients.Of them,28 patients were misdiagnosed as coronary heart disease and 11 patients were misdiagnosed as pneumonia.(4)In the hospitals of secondary medical level the diagnosis depended mainly upon the clinical manifestions of patients and clinical examinations(89.8%).In the tertiary hospitals,the diagnosis of PE was made by using enhanced CT(48.0%),an integrated clinical approach(22.1%),pulmonary ventilation/perfusion scan (12.3%),and pulmonary angiography(10.8%).(5)In the tertiary and secondary hospitals,the percentages of thrombolytic therapy were 17.3%and 14.7%,respectively,(P＞0.05).The percentage of anticoagulant therapy is 63.3%and 77.9%(P＜0.01).The percentage of oral warfarin for at least 3 months were 61.2%and 76.0%(P＜0.01).(6)The anticoagulant or thrombolytic intervention showed higher therapeutic efficiency than the non-intervention(83.6%vs.23.3%,P＜0.01).The mortality of the therapeutic group was lower than that of non-intervention group(9.0%vs.30.0%,P＜0.01).Conclusions PE has no specific symptom and easily leads to misdiagnosis and mistreatment.The diagnosis of PE in the secondary hospitals depended? on general inspection,whereas in the tertiary hospitals,on enhanced CT.Effective intervention can significantly improve outcomes,and standardized guidelines of the diagnosis and treatment of PE should be set in our country.