Conclusion: The polysomnographic (PSG) effects of nasal surgery on positional obstructive sleep apnea/hypopnea syndrome (OSAHS) patients (PPs) and non-positional OSAHS patients (NPPs) were different. Objective: We aimed to determine the PSG data changes after nasal surgery and evaluate the PSG effect of nasal surgery on PPs and NPPs, respectively. Methods: A total of 79 OSAHS patients with nasal obstruction were recruited. Preoperative rhinomanometry and overnight polysomnography were recorded. Patients were distributed into three groups based on the severity level of the apnea and hypopnea indexes (AHI) (mild, moderate, and severe OSAHS). Three groups were each subdivided into two subgroups (PPs and NPPs). Postoperative data were obtained at least 6 months later. Results: After surgery, although nasal resistance decreased significantly in all patients, the total rate of success and response in treating OSAHS was only 22.7%. Grouped on the basis of the severity level of AHI, the lowest SpO(2) increased and AHI, supine AHI, and arousal indexes decreased significantly only in mild OSAHS (p < 0.05). Subdivided according to the presence or absence of positional dependency, the lowest SpO(2) increased and supine AHI decreased significantly in both PPs and NPPs with mild OSAHS and in PPs with moderate OSAHS (p < 0.05). AHI significantly increased in PPs with severe OSAHS (p < 0.05). Supine sleep time was relatively prolonged significantly in PPs with moderate and severe OSAHS (p < 0.05).