Objective To analyze the clinical features of patients with essential thrombocytosis (ET) complicated with coronary heart disease (CHD). Methods Twenty-one patients with ET complicated with CHD who were treated in the First Affiliated Hospital of Zhengzhou University from January 2014 to June 2018 were retrospectively studied. The basic clinical information was recorded in all patients. Results There were 6 male patients and 15 female patients and their mean age was (60.8?±?10.7) years. There were 17 patients with cardiovascular risk factors, 16 patients with positive JAK2V617F gene mutation and 6 patients with previous history of thrombosis. The average platelet count for admission was (880?±?360)?×?109/L. The 21 patients included 7 cases of acute myocardial infarction, 9 cases of unstable angina pectoris and 5 cases of stable coronary heart disease. Seventeen patients had left anterior descending artery involved. Nine patients underwent percutaneous coronary intervention operation and 12 stents were placed. Sixteen patients received double anti-platelet therapy with aspirin combined with clopidogrel or ticagrelor, and 5 patients only received aspirin. Twenty patients had received long-term treatment with hydroxyurea, and one patient received interferon therapy. The average follow-up time was (27?±?17) months. The mean platelet count (395?±?116) ×109/L during the follow-up period was lower than that at admission (880?±?360)?×109/L (P?