The aim of this study is to evaluate the impact of different surgical and postoperative treatment options on the long-term overall survival (OS) in patients with primary single intracranial atypical meningioma. Methods: In this retrospective study, participants were drawn from the Surveillance, Epidemiology, and End Results (SEER) database. Inclusion criteria comprised patients who underwent either gross total resection (GTR) or subtotal resection (STR). The inverse probability weighting (IPW) method using generalized boosted models was used to achieve balance in variables across various treatment groups. Subsequent to IPW, multivariate Cox analysis and Kaplan-Meier analysis were conducted, with OS as the endpoint. Results: GTR was conducted on 1650 patients, while STR was conducted on 1109 patients. Among these, 432 patients who underwent GTR and 401 patients who underwent STR received postoperative radiotherapy (PORT). In the case of patients who were under 60 years old, PORT emerged as a significant protective factor for OS in those who underwent STR (HR 0.44; 95% CI 0.23-0.84; p = 0.013). Survival curves demonstrated that patients who underwent STR with PORT exhibited comparable OS to those who underwent GTR without PORT (p = 0.546). Conversely, for patients aged 60 years or older, PORT emerged as an independent risk factor for both GTR (HR 1.42; 95% CI 1.00-2.00; p = 0.048) and STR (HR 1.81; 95% CI 1.26-2.60; p = 0.001). Conclusion: PORT may contribute to improving OS in primary single atypical meningioma patients under 60 years old who receive STR. However, in older patients who underwent either GTR or STR, the administration of PORT may be associated with a potential risk of OS. Therefore, age should be taken into account in applying PORT therapy, and the optimal treatment strategy for PORT in patients with atypical meningiomas needs to be further explored and validated.