Objective To assess the diagnosis value of 24-hour dynamic electrocardiogram (DCG) on silent myocardial ischemia (SMI) and arrhythmias in elderly patients. Methods Sixty-six continuous elderly patients with coronary heart disease were enrolled, and all of the patients finished the DCG monitors and coronary artery graph or CT examination. The characteristics of SMI, the relationships between SMI and age, involved electrocardiogram leads and coronary angiogram were analyzed. We also evaluated the effects of SMI duration and ST segment depression on the related arrhythmias. Results SMI were found in 48 of 66 patients, and 218 transient SMI attacks were recorded totally. The highest frequency of SMI appeared between 6:00 and 12:00 (110/218, 50.5%). The SMI in 32 patients (32/48, 66.7%) were fast rate dependent and 5 (5/48, 10.4%) were slow rate dependent. Arrhythmias were detected in 38 patients (79.6%). Morbidity of SMI increased with age. One hundred and eighteen transient SMI attacks were recorded in patients aged 65 to 75 years, (4.3±2.9) times per person. Ninety-seven transient SMI attacks were recorded in patients aged 75 to 85 years, (5.2±2.9) times per person. Conclusion SMI is common in elderly patients with coronary heart disease. DCG plays an important role in diagnosing SMI and arrhythmias, which facilitates the evaluation of the risk of sudden death.