This article is focused on the relationship between the algae red tide, vitamin B 1 and B 12 in Dapeng Bay. Before red tide arising, the interrelationship between vitamin B 1 and Nocliluca scientillans is obvious. But it has no effect during the period of red tide. And after red tide, it is more obious than that between vitamin B 1 and Chattonella. The interrilationship between vitamin B 12 and Bonyaulax polygramma is much clearer than that between vitamin B 1 and Gonyaulax polygramma, during red tide.