Objective: To investigate the characteristics of acute myocardial infarction caused by spontaneous coronary artery dissection(SCAD) in young female patients. Methods: In this casecontrolstudy,127 young(≤55 years) female patients with acute myocardial infarction onset within 1 week in Nanjing first hospital, Xuzhou central hospital, affiliated hospital of Xuzhou medical university, and Lianyungang first people's hospital were enrolled between January 2013 and February 2017,and the clinical data were retrospectively analyzed. According to their clinical manifestations and coronary angiography(CAG) results,the patients were divided into coronary atherosclerosis disease(CAD) group(CAG evidenced atherosclerosis, n=83) and SCAD group(CAG detected coronary artery dissection,n=44).The SCAD patients were subdivided into definite group (the results affirmed from intravenous ultrasound or optical coherence tomography, n=21) and probable group (the CAG results highly confirmed to characteristics of SCAD,but no intravenous ultrasound or optical coherence tomography image affirmation,n=23). Then, according to the different treatment strategies, the SCAD patients were subdivided into conservative treatment group(treated with drugs,n=19) and interventional therapy group(treated with percutaneous coronary intervention,n=25). Results: (1)Compared to CAD group, patients in the SCAD group had less risk factors, such as hypertension history (25.0% (11/44) vs. 45.8% (38/83) , P=0.022) and diabetes history (6.8% (3/44) vs. 21.7% (18/83) , P=0.043),and had lower levels of fasting blood glucose (5.34(4.59,5.87) mmol/L vs. 7.12(5.18,8.60)mmol/L, P=0.001),total cholesterol((3.94±1.14) mmol/L vs. (4.91±1.50) mmol/L, P=0.001),triglyceride(1.42 (0.91,1.64) mmol/L vs. 1.89 (1.23,2.45) mmol/L, P=0.005),and low density lipoprotein cholesterol ((2.24±0.91) mmol/L vs. (2.94±1.16) mmol/L, P=0.001),CAG results showed that patients in the SCAD group had more single vessel lesion (88.6% (39/44) vs. 39.8% (33/83) , P=0.001), and their target lesion stenosis was less severe ( (79.2±22.4) % vs. (91.5±12.1) %, P=0.001). (2) The clinical risk factors such as hypertension history, diabetes history, smoking history, family history of cardiology disease, fasting blood glucose,total cholesterol,triglyceride and low density lipoprotein cholesterol were similar between definite group and probable group (all P>0.05). CAG results showed that prevalence of single vessel lesion (100% (21/21) vs. 78.3% (18/23) , P=0.050) and percent of target lesion stenosis ( (76.9±20.6) % vs. (81.2±24.1) %, P=0.529) were similar between definite group and probable group.(3)There were no significant difference in single vessel(84.0% (21/25) vs. 94.7% (18/19) , P=0.370), target lesion stenosis(85.0(70.0,100.0)% vs. 75.0(50.0,90.0)%, P=0.186),and survival rates in hospital(96.0% (24/25) vs. 100% (19/19) , P=1.000) between interventional therapy group and conservative treatment group. Conclusions Prevalence of SCAD is highin young female patients with acute myocardial infarction. Acute myocardial infarction patients with less risk factors of CAD and with CAG showing smooth lesion of narrowing segment and normal finding in the other vessels, are more likely to be diagnosed with SCAD.Acute myocardial infarction patients caused by SCAD have high survival rate either receiving percutaneous coronary intervention or drug treatment.