Abstract: To find out the toxicity dynamics of tetrodotoxin, samples of Amoya caninus were collected from Zhanjiang hanbor of Guangdong Province once a month from January to December in 2012, and the toxicity of the samples was detected by the liquid chromatography-mass spectrometry method to study the regulational change of toxicity. Results showed that the toxin in Amoya caninus were varies with seasonal,spring and April were higher than other period,the highest toxicity was 0.30010-6 in March in spring in the year. The further research revealed that the deposited concentration of toxins was different in different position: Gonad is the main organ to deposite the toxicity, the concentration is reached to 0.43310-6 in March. The secondary is fish liver, fish head, the lowest is fish body; but in July the highest deposited organ is fish skin, The secondary is fish liver, fish head, and the lowest is also fish body; Tetrodotoxin deposited more in fish head than in fish body in March, April, June and October from January to December, the concentration come up to 0.35610-6 in March, but the toxicity is more in fish body than fish head in Febrary and November, and the concentration come up to 0.32510-6 in Febrary.