DNA based biosensors have become increasingly important in hazardous and toxic substances detection.Particularly,the aptamer-based methods have been intensively investigated as potential analytical tools providing desired portability,fast response,high sensitivity and specificity in addition to lower cost against classical methods.Some of the techniques for detection of aptasensors(including colorimetric,fluorescent and electrochemical assays) in the last few years were summarized,and their detection characters and applications were discussed.