Abstract: Tetrodotoxin has a wide range distribution in the wild. In addition to puffer fish, there are many animals, including arthropod, echinodermata, mollusc, worm, newt, frog, etc, contain tetrodotoxin. Although the existing mechanism may be different to various animals, tetrodotoxin plays a very important role in poisonous animal during natural selection and evolvement. In China, the studies of tetrodotoxin are mostly on purification, detecting analysis and antibody preparation, while less work has been performed on its molecular mechanism and ecological function. The present study sums up the related researches on tetrodotoxin′s molecular mechanism and ecological function and tries to illustrate the molecular mechanism of carrying tetrodotoxin in the animals.