Abstract: Objective To study the relationship between the overexpression of sirtuin3 and left ventricular hypertrophy （LVH） in myocardium of spontaneously hypertensive rats （SHR）. Methods 29-week-old SHR （n=24） were randomly divided into two groups: 30-week-old SHR group （fed 1 week, n=11）and 38-week-old SHR group （fed 9 weeks, n=13）. 29-week-old Wistar-Kyoto（WKY） rats （n=20） were used as controls and were randomly divided into 30-week-old WKY group （fed 1 week, n=10）and 38-week-old WKY group （fed 9 weeks, n=10）. The systolic blood pressure （SBP） of tail artery and left ventricular mass/body mass （LVM/BM） were measured. Masson staining analysis was used to exam myocardial interstitial fibrosis of the left ventricular and cardiac ultrasound to measure the cardiac function. Real-time quantitative PCR, immunohistochemistry, and western blotting were used to detect the mRNA and protein expression of sirtuin3. Results Compared to the respective control groups, 30 and 38-week-old SHR showed SBP 30-week（189.0±6.8）vs （103.4±3.6）mm Hg, 38-week （205.6±10.9）vs （116.3±4.3）mm Hg, LVM/BM 30-week （2.94±0.11）vs（2.56±0.21）; 38-week（3.21±0.15） vs（2.68±0.24）, left ventricular end systolic diameter30-week（4.27±0.13） vs（3.59±0.08）mm, 38-week:（5.46±0.14）vs（4.21±0.08）mm, end-diastolic interventricular septum depth 30-week（2.63±0.15） vs （2.09±0.06）mm; 38-week（2.82±0.09） vs （2.35±0.08）mm, end-diastolic left ventricular posterior wall depth 30-week（2.78±0.12） vs （2.15±0.09）mm; 38-week（2.99±0.12） vs （2.44±0.07）mm, as well as sirtuin3 mRNA and protein levels were all significantly increased（all P＜0.05） while the fractional shortening and end-diastolic dimension of left ventricular were significantly decreased（all P＜0.05）. The SHR showed significant left ventricular hypertrophy and left ventricular dysfunction, which aggravated with time. Conclusion Overexpression of sirtuin3 in myocardium is closely related to the left ventricular hypertrophy.