Objective To observe the circadian rhythm of blood pressure and investigate the impact of Norvasc and Tanatril administrated at different time points based on the theory of time therapeutics in hypertensive patients. Methods The 24-hour ambulatory blood pressure was monitored in 130 inpatients and outpatients with grade 3 or 2 hypertension from May 2008 to November 2009. A total of 34 dipper hypertensive patients were grouped into dipper blood pressure group and 5 mg/d of Norvasc and Tanatril were taken by them at 6:00 AM. A total of 96 nondipper hypertensive patients were further divided into three subgroups after adjustment for age and gender: 5 mg/d of Norvasc and Tanatril were taken by group I (n = 30) at 6:00 AM; 5 mg/d of Tanatril at 6:00 AM and 5 mg/d of Norvasc at 18:00 PM by group Ⅱ (n = 32); 5 mg/d of Norvasc at 6:00 AM and 5 mg/d of Tanatrilat 18:00 PM by group Ⅲ(n=34).The 24-hour ambulatory blood pressure monitoring was performed again after four weeks treatment and 24-hour mean systolic blood pressure(24 hSBP),24-hour mean diastolic blood pressure(24 hDBP),daytime and nighttime mean systolic blood pressure(dSBP,nSBP)and daytime and nighttime mean diastolic blood pressure(dDBP,nDBP),were analyzed.Results The 24 hSBP,24 hDBP and dSBP,and dDBP were reduced from(154.3±5.6),(95.4±3.1),(158.7±6.5),(99.6±3.7)mmHg to(137.2±3.9),(82.5±2.7),(139.7±3.8),(85.2±3.5)mmHg,respectively,in dipper blood pressure group(t=2.124,2.356,2.278,2.449,all P<0.05).The 24 hSBP and 24 hDBP of the three groups in nondipper blood pressure were decreased from(154.4±6.1),(156.7±6.7),(156.6±5.2),(95.8±2.8),(94.9±3.8),(95.7±3.2)mmHg to (139.6±4.1),(134.5±4.6),(133.4±3.5),(83.5±4.2),(80.8±5.6),(81.6±4.7)mmHg,respectively(t=2.038,2.040,2.135,2.142,2.213,2.216,all P<0.05).dSBP and dDBP were decreased from(158.6±3.50),(158.4±5.6),(159.5±4.),(98.4±3.7),(99.6±3.7),(83.9±5.2)mmHg to(138.9±5.4),(136.7±4.1),(137.4±6.4),(85.8±5.3),(83.6±5.1),(83.9±5.2)mmHg,respectively(t=2.021,2.252,2.261,2.217,2.167,2.076,all P<0.05).nSBP and nDBP were decreased from(146.7±6.9),(149.8±3.9),(150.2±4.1),(93.7±4.2),(95.7±4.3),(93.4±3.3)mmHg to(133.7±4.6),(129.8±5.7),(127.6±2.8),(87.8±2.9),(78.5±6.4),(77.8±4.8)mmHg,respectively(t=1.798,2.032,2.014,1.864,2.157,2.166,all P<0.05).There were significant differences in nSBP and nDBP among all groups after treatment(F=2.32,2.17,all P<0.05),and the effect of the drugs was better in groug Ⅱ and Ⅲ than in group Ⅰ(q=3.17,4.03,3.32,4.19,all P<0.05),but there were no significant differences between group Ⅱ and Ⅲ(P>0.05).Conclusions Blood pressure can be controlled effectively by taking two antihypertensive medictions in the morning in hypertensive dipper patient but the blood pressure of nondipper hypertensive patients were able to be controlled more efficiently by taking the two antihypertensive medictions separately in the morning and at the evening compared with that taking the two drugs together in the morning.