Objective To investigate the clinical features, diagnosis, treatment and prognosis of the elderly acute myocardial infarction (AMI) patients complicated with gastrointestinal bleeding (GIB). Methods All 90 patients diagnosed with AMI in our department from January 2012 to April 2014 were recruited in this study. They were divided into AMI group (n=30, without GIB), AMI-GIB group (n=30, GIB occurred after AMI) and GIB-AMI group (n=30, GIB followed by AMI). The clinical features and mortality after 6 months’ follow-up were analyzed. Results The ratio of the patients with a history of gastrointestinal diseases were significantly higher in the AMI-GIB and GIB-AMI groups than in the AMI group (P<0.05), and there were more patients undergoing percutaneous coronary intervention (PCI) in the AMI-GIB group than in the other 2 groups (P<0.05). Activated partial thromboplastin time (APTT) was obviously longer, and the more patients received blood transfusion and proton pump inhibitors (PPIs) treatment, while that of those receiving aspirin was less in the AMI-GIB and GIB-AMI groups than in the AMI group (P<0.05). The level of D-dimer and the ratio of blood urea nitrogen (BUN)/serum creatinine (SCr) were much higher in AMI-GIB group than in the other 2 groups (P<0.05). The level of hemoglobin (Hb) and the efficacy of anti-platelet therapy were significantly lower in the GIB-AMI group than in the other 2 groups (P<0.05). The mortality was significantly higher in the AMI-GIB group than in the other 2 groups (P<0.05). Conclusion The occurrence of AMI complicated with GIB is closely associated with the histories of gastrointestinal ulcers and PCI procedure. The ratio of BUN/SCr and level of D-dimer might be the predictive indicators for prognosis of GIB after AMI.