Aim To explore the effect of abdominal obesity on blood pressure variability （BPV） in patients with primary hypertension. Methods A total of 159 patients who were admitted to our hospital because of simple hypertension were enrolled in this study and divided into two parts respectively based on body mass index （BMI） and abdominal circumference （AC）. For part 1, patients were divided into normal BMI group （BMI ＜28 kg/m², n79） and high BMI group （BMI≥28 kg/m²,n80） for part 2, patients were divided into normal AC group （male＜90 cm, female＜85 cm, n72） and high AC group （male≥90 cm, female≥85 cm, n87）. And the characteristics of their BPV were observed respectively through 24 hour ambulatory blood pressure monitoring （ABPM）. Rseults The coefficients of variation （CV） of both the 24 hour mean systolic blood pressure and daytime mean systolic blood pressure of the observation group （BMI≥28 kg/m², n87） were higher than those of the control group （BMI ＜28 kg/m², n79）, and there were statistically significant differences between the observation group and the control group （P<0.05 ）. The CV of nighttime mean systolic and diastolic blood pressures of male patients in both the observation group and the control group were higher than those of female ones in the two groups, and the differences were statistically significant （P<0.05）. In the observation group, the CV of 24 hour mean systolic blood pressure of male patients were higher than that of female ones, and the differences were statistically significant （P<0.05）. The CV of both the 24 hour mean systolic blood pressure and the daytime mean systolic blood pressure of patients of the observation group （AC of male≥90 cm, AC of female≥85 cm, n87） were higher than those of the control group, and the differences were statistically significant （P<0.05）. The CV of nighttime mean diastolic blood pressure of male patients of both the observation and the control groups were higher than that of female ones of the two groups, and the differences were statistically significant （P<0.05）. In the observation group, the CV of 24 hour mean systolic blood pressure of male patients were higher than that of the female ones, and the differences were statistically significant （P<0.05）. Conclusions Their BPV will increase when the patients with hypertension have abdominal obesity. And this effect is more obvious in male patients than that in female ones. So more attetion should be paid by doctors to the regulation of BPV among patients with hypertension, especially male ones with abdominal obesity, as controling the patients’ blood pressure.