Aim To study the effect of hypertension and diabetes on cardiac anatomic structure by Multilayer spiral CT. Methods 450 patients were categorized as essential hypertension group (n=150), essential hypertension with type 2 diabetes group (n=150) and control group (n=150), the cardiac structure according to the results of CT measurements was evaluated. Results For left ventricular cavity area and left ventricular maximum thickness, cross-sectional area of the heart between control group and essential hypertension groups, control group and hypertension and diabetes group, the differences was statistically significant (P＜0.05). For left ventricular minimum thickness between essential hypertension group and hypertension and diabetes group, the difference was statistically significant (P＜0.05). For coronal plane area and the volume of the heart between control group and hypertension and diabetes group, the difference was statistically significant (P＜0.05). Conclusion Hypertension can affect the cardiac structure mainly on the horizontal direction and diabetes can affect the cardiac structure on the horizontal and vertical direction.