Abstract: Aim To compare the effects of the conventional fast release（N CF） and nifedipine gastro intestinal therapeutic system （N GITS） on blood pressure and heart rate variability（HRV） in hypertensive patients. Methods Twenty five essential hypertensive patients were given N CF in the first 4 weeks and N GITS in the following 4 weeks. Holter monitor was carried out at the end of 4th and 8th week. Both 24 h and 5 min （Time Ⅰ 5:30AM～5:35 AM, Time Ⅱ 10:00 AM ～10:05 AM） HRV were analyzed. Results N GITS reduced blood pressure more significantly （32.0±23.9, 19.3±10 6 mmHg） than N CF （24.5±24.5, 15.0±9.7 mmHg, P ＜0 001）. After taking N GITS, the normal difference of day time and night time HRV was reserved; the rMSSD and PNN\-\50\ in 24 hour HRV （25.7±9.5, 5.3±5.1） were much higher than those after N CF（22.2±10 5, 3.40±3.41, P ＜0 05）; and the TP, LFn and LF/HF in 5 minute HRV were also much higher in Time Ⅱ（814.6±570 7, 66.8±24.7, 4.7±4.9） than in Time Ⅰ（371.6±336.5, 50 2±23.8, 2.0±3.1, P ＜0 05）. After taking N CF,in 5 min HRV, the TP in Time Ⅱ（1514.3±1495.1） was higher than in Time Ⅰ（472.9±887.9, P ＜0 05）; but the LFn in Time Ⅰ（67.9±14.7） was higher than in Time Ⅱ（54.1±21.9, P ＜0 05）; and there was no difference of LF/HF between these two times. Conclusion The N GITS had better antihypertensive effect than the N CF. The N GITS did not activate the sympathetic nerve system but increase the vagus nerve activity with the reservation of the circadian rhythm of HRV.