The invention relates to the technical field of biological medicines, and discloses an application of a combined gene in preparation of a product for diagnosing esophageal squamous carcinoma. The combined gene comprises the following genes of a CCL20 gene, a GSTP1 gene, an HSPB1 gene, a KRT14 gene, a KRT15 gene, an S100A8 gene, an S100A9 gene and a TACSTD2 gene. The invention also discloses an application of the combined gene in preparation of a pharmaceutical composition for treating the esophageal squamous carcinoma. Compared with single gene expression detection of the esophageal squamous carcinoma in the prior art, the combined gene has higher specificity and higher diagnosis efficiency, can significantly improve the detection sensitivity and specificity, can accurately, conveniently and efficiently perform esophageal squamous carcinoma early diagnosis and large-scale screening, and fills up the blank of an existing diagnosis technology, so that effective treatment measures are provided for esophageal squamous carcinoma patients in time, and prognosis is improved.