Objective To evaluate the application value of multi-slice spiral CT in assessing cardiac function in patients with severe coronary artery stenosis. Methods The coronary artery stenosis degree was determined by the multi-slice spiral CT angiography (CTA) examination results and the vascular lumen diameter, and according to this judgment results, 180 cases of patients with coronary artery stenosis were divided into four groups: the mild stenosis group (n=38), the moderate stenosis group (n=58), the severe stenosis group (n=48) and the occlusion group (n=36). And the four groups were performed multi-slice spiral CT cardiac scanning. The left atrial function parameters were measured, including left atrial end diastolic volume (LAEDV), end-systolic volume (LAESV), left ventricular stroke volume (LVSV), left ventricular mass (LVMM), left atrial ejection fraction (LAEF), and so on. And the echocardiography was used to measure the abovementioned parameters. Results There were no significant differences in left atrial function parameters between echocardiography and multi-slice spiral CT (P>0.05). The results of multi-slice spiral CT showed that there were significant differences in left ventricular parameters ( LAEDV, LAESV, LVSV, LVMM and LAEF) between the mild stenosis group, the moderate stenosis group, the severe stenosis group and the occlusion group (P<0.05). There was no significant difference in the left ventricle parameters between the mild stenosis group and the moderate stenosis group, and there was no significant difference in the left ventricle parameters between the severe stenosis group and the occusion group (P>0.05), but the levels of LAEDV, LAESV and LVMM were significantly higher and the levels of LVSV and LAEF were significantly lower in the severe stenosis group and the occlusion group compared with those in the mild stenosis group and the moderate stenosis group (P<0.05). With the coronary artery stenosis degree increased, the levels of LVEDV, LVESV and LVMM were increased and they were positively correlated (r= 0.38, 0.35, 0.42, P<0.05), and the levels of LVEF and LVSV were decreased and they were negatively correlated (r= -0.32, -0.41, P<0.05). Conclusion Multi-slice spiral CT quantitative assessment is accurate and reliable in the severe coronary artery stenosis and left ventricular systolic function, and can simultaneously assess coronary artery stenosis and left ventricular function.