〔Abstract〕 Objective To explore the effect of cardiac color Doppler ultrasound combined with electrocardiogram (ECG)on the diagnosis and detection rate of hypertensive heart disease, so as to provide theoretical reference for clinic. Methods 60 patients with hypertensive heart disease treated in Changshu Second People's Hospital from July 2019 to June 2021 were selected. All patients were examined by ECG and cardiac color Doppler ultrasound. The diagnostic effects of ECG alone (separate group) and ECG combined with cardiac color Doppler ultrasound (combined group) were compared. Results The positive diagnostic rate of the combined group was 100% (60 / 60), and there was no significant difference compared with 95% (57/60) in the control group (P > 0.05); The detection rates of left ventricular enlargement, left ventricular hypertrophy, aortic dilatation and aortic hypoelasticity in the combined group were significantly higher than those in the control group (P < 0.05). There was no significant difference in the detection rates of arrhythmia and ST-T changes between the two groups (P > 0.05). Conclusion ECG is effective in the diagnosis of hypertensive heart disease. If it can be combined with cardiac color Doppler ultrasound, the diagnostic effect and detection rate can be improved.