Objective To investigate the corrected factors of blood gas analysis in patients with obstructive sleep apnea hypopnea syndrome(OSAHS). Methods212 cases of patients who underwent standard polysomnography and were diagnosed OSAHS were included. Age, BMI, polysomnography parameters, renal function, lung function and blood gas analysis were recorded. The correlation between blood gas analysis[pH, partial pressure of oxygen(PaO₂), carbon dioxide partial pressure(PaCO₂)] and clinical, polysomnographic, and metabolic parameters were evaluated by the Pearson’s correlation test. The multivariate linear regression model was performed to examine determinants of blood gas analysis(pH, PaO₂, PaCO₂). Results There were significant correlations between pH and AHI, LaSO₂, MSaO₂, Ts90%, ODI, DLCO/VA%. Pearson’s correlation also revealed a significant association between PaO₂ and BMI, AHI, LaSO₂, MSaO₂, Ts90%and ODI. Additionally, PaCO₂ also revealed a significant association between AHI, AHTI, LaSO₂, MSaO₂, Ts90%, ODI and DLCO/VA%. When using blood gas analysis(pH, PaO₂, PaCO₂)as a dependent variable, age and LaSO₂ significantly predicted pH after adjustment for confounders(β=0.428, P=0.000; β=0.289, P=0.002, respectively), LaSO₂and BMI significantly predicted PaO₂(β=0.269, P=0.007; β=-0.261, P=0.009), LaSO₂ and DLCO/VA% significantly predicted PaCO₂(β=-0.392, P=0.000; β=0.213, P=0.025). Conclusion Acid-base balance and daytime hypoxemia are related to age and obesity, respectively, and pulmonary diffusion has certain influenceon hypercapnia. In addition, nocturnal hypoxemia is an importantdisorder leading to the change in daytime blood gas analysis in patients with OSAHS.