〔Abstract〕 Objective To monitor changes in blood pressure during rapid eye movement(REM) and non-REM(NREM) sleep in patients with obstructive sleep apnea(OSA), and to analyze the effect of obstructive respiratory events on blood pressure during different sleep stages. Methods A cross-sectional trial was adopted on 1 219 patients diagnosed with OSA. The obstructive respiratory events and blood pressure of patients during REM and NREM sleep were monitored. Additionally, the symptoms of blood pressure fluctuations in OSA patients during different sleep periods and the effects of obstructive respiratory events on blood pressure fluctuations were analyzed. Results SBP and DBP during REM and NREM sleep both tended to rise as OSA worsened. The differences in SBP, DBP, mean apnea time(MAT), mean hypoventilation time(MHT), lowest oxygen saturation(LSpO2), and oxygen desaturation index(ODI) in different sleep periods were statistically significant(P<0.05). Multiple linear regression analysis revealed that SBP during REM sleep was negatively correlated with LSpO2and the apnea-hypopnea index(AHI)(P<0.05), but positively correlated with ODI(P<0.05). DBP during REM sleep was negatively correlated with LSpO2, AHI, and MHT(P<0.05), but positively correlated with ODI(P<0.05); SBP and DBP during NREM sleep were negatively correlated with LSpO2(P<0.05). Conclusion As the severity of OSA increases, the blood pressure values during different sleep periods rise accordingly. The blood pressure levels during REM sleep in OSA patients are higher than those during NREM sleep. LSpO2is an important factor causing blood pressure changes in different sleep periods. AHI, ODI, and MHT are important factors causing blood pressure changes during REM sleep.