This research aimed to investigate the prognostic factors of oral squamous cell carcinoma (OSCC), especially the role of age. A total of 33619 cases of OSCC were received from the Surveillance, Epidemiology, and End Results database during 2005–2015. Kaplan-Meier curves of 5-year overall survival rates and 5-year cancer specific survival rates were performed, and univariate and multivariate Cox regression analysis as well as competing risk model were used to help understand the relationship between various factors and mortality of OSCC. Compared to 18–39 years old group, the older age was an important predictor of worse prognosis. The multivariate analysis of overall survival (OS) were 50–59 years old (HR, 1.32; 95% CI, 1.17–1.48; p ≤ .001), 60–69 years old (HR, 1.66; 95% CI, 1.42–1.87; p ≤ .001) and 70 + years old (HR, 3.21; 95% CI, 2.86–3.62; p ≤ .001) respectively, while the specific value of competing risk model were 60–69 years old (HR, 1.21; 95% CI, 1.07–1.38; p = .002) and 70 + years old (HR, 1.85; 95% CI, 1.63–2.10; p ≤ .001). In addition, female gender, unmarried, Blacks, tumor in floor of mouth, size and higher TNM classification were also other predictors that signify significant clinically deterioration of OS / CSS. Our research revealed that age was an important factor in explaining the difference of survival in the whole process of OSCC. It’s suggested that we should pay attention to the influence of age on diagnosis, treatment and prognosis in the clinical process.