Abstract: Objective To explore the effects of low tube voltage and contrast dose on the prospective ECG gating coronary artery imaging in overweight patients.Methods A total of 80 overweight patients were randomly divided into control group (traditional tube voltage and contrast medium dose) and observation group (low tube voltage and contrast medium dose),and effect of prospective ECG gating coronary artery imaging was compared.Results In the observation group,the excellent rate of imaging quality was 90％,and which in the control group was 92.5％ (P ＞ 0.05).There were significant differences in values of CT coronary artery imaging,image noise,image signal-tonoise ratio and radiation dose between two groups (P ＜ 0.05).Conclusion Low tube voltage and contrast dose can significantly reduce the patient's radiation dose.