Objective To investigate the risk factors of non-dipper hypertension in elderly patients with sleep-disordered breathing. Methods A total of 124 elderly inpatients with hypertension associated with sleep-disordered breathing in Clinical Medical College of Yangzhou University from July 2019 to December 2020 were recruited in this study, and then divided into dipper hypertension group (n=61) and non-dipper hypertension group (n=63) according to the rate of blood pressure decrease during day and night. SPSS statistics 23.0 was used to perform the statistical analysis. Student′s t test or Chi-square test was employed for intergroup comparison based on different data types. Logistic regression analysis was adopted to analyze the risk factors for non-dipper hypertension. Results As compared with the dipper hypertension group, the non-dipper hypertension group had significantly larger neck circumference and body mass index (BMI), and higher 24-hour mean systolic blood pressure (24h MSBP), nocturnal mean SBP (nMSBP), 24h mean pulse pressure difference (24h MPP), apnea hypopnea index (AHI), times of apnea, oxygen desaturation index (ODI),pulse oxygen decline rate, and carotid intima-media thickness (CIMT, with the left side more obvious than the right one in same group), but remarkably lower lowest oxygen saturation (LSaO₂) at night (P<0.05). The results of logistic regression analysis showed that ODI (OR=1.423,95%CI 1.230-2.566, P<0.001), CIMT (OR=1.965,95%CI 1.031-2.752, P<0.001)and pulse oxygen decline rate (OR=1.676,95%CI 1.007-2.889, P<0.001) were risk factors for non-dipper hypertension in elderly patients with sleep-disordered breathing. Conclusion Sleep disordered breathing is significantly related to the change of nocturnal blood pressure rhythm. ODI, CIMT and pulse oxygen decline rate are important risk factors for no-dipper hypertension in elderly patients with sleep-disordered breathing. Reducing nocturnal hypertension, djusting non-dipper to dipper circadian rhythm, and improving sleep quality are of great benefit to these patients.