Abstract: AIM To explore the characteristics of heart rate variability (HRV) in elderly orthostatic hypotension patients with different common chronic diseases. METHODS 267 long-term patients who were older than 60 years of age were devided into an orthostatic hypotension group (OH group) and non-orthostatic hypotension group (non-OH group). After both groups completed a 24-hour-ambulatory ECG, HRV of time and frequency domain were compared between the two groups. Additionally, the HRV indexes of different patients with certain disease states were analyzed and compared. RESULTS In the non-OH group, from the time of the local indicators, hypertension was the highest, coronary heart disease was second, and diabetes mellitus was the lowest. With regard to frequency region, hypertension was the highest, diabetes mellitus was second, and coronary heart disease was the lowest. In the OH group, from the time locality index, high blood pressure was the highest, followed by coronary heart disease, and diabetes mellitus ws the lowest. According to the regional indicator HF, hypertension was the highest, and diabetes mellitus was second, with the lowest being coronary heart disease, but from LF, hypertension was the highest, and the difference between coronary heart disease and diabetes mellitus was not significant. Compared with those of the non-oh group and the indicators of disease, the OH group and patients with diabetes mellitus had the most significant decline in regional indicators. The frequency and regional indicators of 3 common chronic diseases in OH group were significantly decreased (P<0.05, P<0.01). CONCLUSION In elderly patients with low blood pressure, there is a significant decrease in regional indicators in patients with diabetes mellitus and a significant decrease in frequency of patients with coronary heart disease.