Objective: To analyze the characteristics of modifiable risk factors, coronary artery lesions, reperfusion and drug treatment in young women hospitalized for first acute coronary syndrome (ACS). Methods: Clinical data of young adults of 18 to 44 years hospitalized for first ACS in Beijing Anzhen Hospital between January 2007 and December 2017 were analyzed. A total of 7 106 young adults with ACS were enrolled, 6 593(92.8%) were male and 513(7.2%) were female. There were 2 254(31.7%) patients with ST-segment elevation myocardial infarction (STEMI), 704(9.9%) patients with non-ST-segment elevation myocardial infarction (NSTEMI) and 4 148(58.4%) patients with unstable angina (UA). Clinical characteristics, laboratory examinations, coronary angiography and medical treatment were recorded. The gender differences in the characteristics of modifiable risk factors and coronary artery stenosis in young patients with ACS were also analyzed. Results: Dyslipidemia (87.5%) followed by overweight/obese(83.8%) and smoking (68.5%) were most prevalent modifiable risk factors in men. Dyslipidemia (63.4%), overweight/obese (63.4%) and hypertension (45.5%) were most prevalent modifiable risk factors in women. The prevalence rates of at least 1 risk factor in men and women patients were 99.1% and 87.9%, respectively. Between 2007 and 2017, the rates of hypertension and overweight/obese in men increased, and the rates of dyslipidemia and smoking decreased (trend P<0.01). The changes of incidence of modifiable risk factors through the years in women were not statistically significant. The rate of men receiving coronary angiography was higher than that in women (96.6% vs 93.4%, P<0.01). Women were more likely to suffer left main coronary artery disease than men (7.3% vs 4.1%, P<0.01). Multi-vessel coronary artery disease occurred more in men (43.4%), and single vessel coronary artery disease occurred more in women (47.0%). Women presented with STEMI had a lower probability of receiving clopidogrel/ticagrelor (76.8% vs 86.1%, P<0.01) and angiotensin Ⅰ-converting enzyme inhibitor/angiotonin receptor blocker (ACEI/ARB) (46.5% vs 60.2%, P<0.01) than that in men. Women presented with UA had a lower probability of receiving aspirin (86.3% vs 89.9%), clopidogrel/ticagrelor (69.7% vs 75.6%), statin (78.8% vs 85.0%) and ACEI/ARB (32.7% vs 38.6%) than men (all P<0.01). Women had a higher probability of presenting Killip II-IV than men (38.6% vs 25.6%, P<0.05). Conclusion: The majority of young patients with ACS were men. The prevalence rates of modifiable risk factors are very high in both man and woman. Compared with man, women with AMI are more likely to develop acute heart failure with lower probability of reperfusion and drug treatment.