This invention provides a small molecule oligonucleotide aptamer binding to T-2 toxin specifically, and the sequence of the ssDNA aptamer is SEQ ID NO: 1. Through the graphene oxide separation-based Systematic Evolution of Ligands by Exponential Enrichment, single-stranded oligonucleotide aptamer with high affinity and specific identification of T-2 toxin was obtained in vitro selection. The aptamer has a broad application prospect, which can be used for separation and enrichment of trace T-2 toxin in the sample. It can also be used as a reporter aptamer for the detection of T toxin in food by means of functional groups labeling and other means.