The invention discloses an application of a biomarker to assessment of oral squamous cell carcinoma hazard levels. The biomarker is GSDMA and is used for detecting oral squamous cell carcinoma sampleswith different differentiation grades to discover that the biomarker presents significant differences in oral squamous cell carcinoma samples with different hazard levels, and prompt to apply the GSDMA to grading judgement of oral squamous cell carcinoma so as to instruct the doctors to adopt different treatment ways for the oral squamous cell carcinoma in different progresses and then improve the treatment effect.