Abstract: Objective To examine the influence of the opportunity and frequency of orthostatic blood pressure measurements on the detection rate of orthostatic hypotension（OH）. Methods From March 2012to January 2013,a total of 767subjects were recruited,including 193clinic or hospitalized patients with OH related symptoms from the General Hospital of Guangzhou Military Command of People’s Liberation Army（PLA）and 574subjects without OH related symptoms from the Health Department of 75645Unit of PLA. According to the OH diagnosis criteria,all subjects were classified into the non-OH group（n=683）and the OH group（n=84）. Data on body height and weight,waist and hip circumstances,resting heart rate were recorded at baseline. At both the morning and afternoon of 1st and 8th days,systolic and diastolic blood pressures were respectively measured at both recumbent and orthostatic positions,and then orthostatic changes in systolic and diastolic blood pressures were calculated. The detection rate of OH and the orthostatic changes of blood pressures were analyzed. Results Subjects in OH group were older than those in non-OH group,and the percentages of Parkinson’s disease,patients under antihypertensive treatment,and female gender were higher,but waist and hip circumstances were lower in OH group. As indicated by the Bland-Alman method,the consistency in the orthostatic changes of blood pressures was poor between the morning and afternoon measurements,whereas this consistency was better between the 1st and 8th days at the same measurement time. There was no statistical difference in the detection rate of OH between the 1st（69.1%）and8th（53.6%,P＞0.05）days. In contrast,the detection rate was higher in the morning（75.0%）than in the afternoon（38.1%,P＜0.01）. Conclusion Repeated measurements of orthostatic blood pressures can improve the detection rate of OH,and it is recommended to perform the measurements in the morning.