Abstract: In this study, we used LC-MS/MS to study the lipophilic toxins in phytoplankton and three bivalves (Crassostrea angulata, Mytilus edulis, Pteria margaritifera) in Dapeng cove of Daya bay in four seasons in 2017. The results showed that there were two kinds of toxigenic algae in the water, i.e., Dinophysis caudata and Pseudo-nitzschia spp. DTX, PTX, GYM and DA were detected in the concentrated phytoplankton of net samples. The cell abundance of D. caudata was the highest in spring (420 cells/L), and also distributed in other seasons (less than 50 cells/L) The highest cell abundance of Pseudo-nitzschia spp. also appeared in spring, followed by summer, and the cell abundance was lower in autumn and winter. Correspondingly, DA was detected only in spring and summer, but not in autumn and winter. Four kinds of toxins, OA, PTX, GYM and DA were detected in shellfish samples. OA and PTX were not detected in the musscle of three shellfish samples, but they were detected in the digestive gland, which mainly appeared in autumn. GYM and DA were detected both in the digestive gland and muscle of all shellfish samples, but the DA concentration was significantly lower than that of GYM. The contents of OA, PTX and DA in digestive gland were significantly higher than those in musscle (P < 0.01), but GYM concentration showed no significant difference in digestive gland and muscle (P > 0.05). Generally speaking, the content of all lipophilic toxins measured in this survey is low and within the safe range of edible.