Objectives: Many studies have revealed that the dysfunction of autonomic nervous system (ANS) contributes to the emergence and development of numerous cardiovascular diseases. Essential hypertension patients with dysfunction of ANS are more likely to suffer from target-organ damages earlier. In our study, we investigated the correlation between left ventricular hypertrophy (LVH) and ANS. Methods: In a retrospective study, 371 hospitalized patients with EH were enrolled in our study. The function of ANS was evaluated by blood pressure variability (BPV) and heart rate variability (HRV) synchronously, which were tested by receiving ambulatory blood pressure (ABPM) and dynamic electrocardiography monitoring (Holter) in a same 24 hours. Based on echocardiography, left ventricular mass were calculated by Devereux Formula. LVH was defined as LVMI ≥ 125 g/m2 for male and LVMI ≥ 110 g/m2 for female or LVDST/ LVDPWT ≥ 11 mm. Results: Compared with the control group, the LVH group had higher 24hSBP, 24hDBP, 24hMBP, 24hPP, dSBP, dDBP, dMBP, dPP, nSBP, nDBP, nMBP, 24hSSD, dSSD, nSSD, nDSD and lower nSBPF, nDBPF by analyzing ABPM. LVH group also showed higher LF, LF/HF which can reflect the HRV and indicate the increasing excitability of sympathetic nervous system (Table 1). In multiple linear stepwise regression analysis: nDSD and LF/HF are both positive correlated with LVMI (r are 0.07 and 1.512 respectively, P < 0.01). Conclusion: The dysfunction of ANS contributes to the emergence and development of LVH in patients with EH. The dysfunction is always caused by the increasing excitability of sympathetic nervous system.