Abstract: Aptamer is a kind of synthetic oligonucleotides by in vitro screening of systematic evolution of ligands by exponential enrichment（SELEX）, which can bind to different targets, such as small organic molecules, proteins, drugs or antibiotics etc., with high affinity and specificity. Due to their special characteristics of a wide range of targets, good stability, simple preparation and easy modification in vitro, aptamers have been widely used in disease diagnosis, clinical therapy, bioanalysis, drug development and other fields. The SELEX method using pesticides as targets has been preliminarily applied in the determination of pesticide residues. Based on recent literatures, this paper describes the finding history and merits of aptamers, the principle as well as separation methods in aptamers sieving process by use of SELEX. Applications of aptamers in pesticides, antibiotics, metal ions, biotoxins, pathogenic microorganism and proteins were also summarized. Furthermore, the prospect of aptamers based detection techniques were proposed.

Key words: Aptamer, Systematic evolution of ligands by exponential enrichment, Preparation, Analytical application