Objectives: The purposes of this paper are to study the changes of left ventricular diastolic function of essential hypertension (HT). Methods: Sixty patients with HT in different phase were examined by using echocardiography. Early diastolic peak flow velocity (VE), end diastolic peak flow velocity (VA) and E/A ratio were measure with the pulsed Doppler echocardiography. Results: The results shown that in normal controls VE and VA (cm/s) were 82± 13 and 51± 12, respectively, with E/A> 1. In the HT groups, the first phase patients, VE and VA were 80± 13 and 50± 11, with E/A> 1, and there were not statistically different compared with normal control group (p> 0.05). In the second phase patients, VE and VA were 58± 13 and 52± 12, with 14 cases of E/A> 1 and six cases of E/A< 1, and there were significantly different compared with normal control. In the third phase patients, VE and VA were 40± 12 and 53± 12, with three cases of E/A> 1 and 17 cases of E/A< 1, and there were significantly different compared with normal controls (p< 0.01). Conclusions: We suggested that HT in first phase did not have changes of left ventricular diastolic function, in the second phase HT had often changes, in the third phase HT had significant changes. Measurement of VE, VA and E/A ratio has been proved to be valuable for valuating the left ventricular diastolic function changes of HT.