Background Studies on the epidemiology and prognosis of primary ocular adnexal lymphoma (POAL) are scarce for its low occurrence. The goal of our research was to assess the epidemiologic characteristics, prognostic variables and survival of POAL patients. Methods The Surveillance, Epidemiology and End Results (SEER) database was used to collect data on patients identified with POAL from 1975 to 2011 and the incidence rate of POAL from 1975 to 2017. To discover independent predictive markers for overall survival (OS) and disease-specific survival (DSS), multivariable Cox regression analysis was utilised. The independent prognostic factors found by multivariate Cox regression analysis were used to generate a nomogram. Results A total of 2839 patients were diagnosed with POAL, with an average age of 64.1 years. The total incidence of POAL was 2.51/1000000 (according to the overall adjustment of the 2000 American standard) from 1975 to 2017, and the annual percentage change (APC) was 2.47 (95% confidence interval 1.64-3.32, p < 0.05), showing a sharp upward trend. After multivariate Cox regression analysis, age, gender, year of diagnosis, marital status, primary site, laterality, pathological type and treatment strategy were evaluated as independent prognostic factors of OS or DSS (p < 0.05). A nomogram was constructed to forecast the DSS of 1, 3, 5 and 10 years. The concordance index (C-index) and the calibration plots demonstrated the robustness and accuracy of the nomogram. Conclusions Although POAL is sporadic, the incidence has generally increased in the past 36 years. In recent years, survival rates have risen, and radiotherapy can render better OS and DSS. The nomogram specially made for POAL is robust and precise in predicting the DSS of 1, 3, 5 and 10 years.