Coronary artery ectasia (CAE) patients were more prone to present with acute myocardial infarction (AMI), this case-control research aimed to explore the underlying factors relating AMI for them. This study investigated a serial of 119 patients who underwent coronary angiography and were diagnosed as CAE between the years 2016 and 2017 at the Beijing Friendship Hospital; 32 of the patients developed AMI and 87 did not develop AMI. The possible factors relating to AMI, including disease history, cardiovascular risk factors, thrombotic condition, inflammation status, and coronary imaging characteristics, were comprehensively compared between CAE patients with and without AMI. CAE patients with AMI had a lower antiplatelet rate, a higher blood low-density lipoprotein cholesterol level, increased neutrophil to lymphocyte (NL) ratio, higher Gensini score, and larger proportions of Markis type II. Logistic regression analysis also indicated that AMI history, lower antiplatelet rate, higher NL ratio, higher low-density lipoprotein cholesterol level and Gensini score, as well as Markis type II were associated with AMI in CAE patients. AMI history, lower antiplatelet treatment rates, poor blood lipid control and higher coronary stenosis extent, higher inflammatory response, and Markis type II were closely related to the incidence of AMI in CAE patients.