Abstract: In this study we explored the bioaccumulation of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) by Amphidinium carterae Hulburt under different N/P ratios (1, 4, 16, 64, 128) in different growth phases. Specifically we exa-mined the algal specific growth rate and the biochemical composition including lipid and carbohydrate, as well as the relationship between the amount of bioaccumulated BDE-47 and the biochemical composition. The results showed that the amount of bioaccumulated BDE-47 was 1.3 ng/(106 cells) when the N/P ratio was 16 in the lag phase which was significantly lower than those under other N/P ratios. In the log and stationary phase, the bioaccumulated BDE-47 under N/P ratios of 64 and 128 was significantly richer than those under other ratios. Under the two N/P ratios mentioned above, the amounts of bioaccumulated BDE-47 in the log 2.5-2.6 ng/(106 cells) and stationary phases were 1.5 and 2.4 times higher than those under other N/P ratios respectively. It reached to 3.6 ng/(106 cells) under N/P ratio of 128 in stationary phases. There was a positive correlation between the amount of bioaccumulated BDE-47 and cellular lipid, with the R2 value of nearly 0.6. Our results showed that the lipid content was positively correlated with the bioaccumulation of BDE-47; therefore the N/P ratio could affect the amount of bioaccumulated BDE-47 by altering the lipid content.