Abstract: Aptamers are single-stranded oligonucleotides with high affinity and selective binding to the target and can be screened by SELEX techniques.SELEX technology can choose a wide range of target molecules, including proteins, peptides, nucleotides, dyes, amino acids, metal ions, biological toxins.Aptamer selected by SELEX has specific characteristics.With the advantages of short cycle, the library can be chemical synthesis to avoid the animal experiments.Food harmful small molecules mainly include mycotoxins, pesticides, veterinary drugs, metal, prohibited additives, mainly in food, grain, feed, all kinds of food, water.These harmful small molecules through the food chain into the human and animal body and create a serious threat to its health.A variety of high affinity and specific sensors and detection methods have been reported in previous, aptamers are used as identification element for food safety, environmental testing and biomedicine.Unlike previous reports, this paper mainly foucusses on the advances in aptamer for the detection of toxic small molecules in food.