Abstract: Under the temperature between 20 ℃and 30 ℃,Dicrateria zhanjiangesis was cultured in the seawater containing different concentr ate d(0 .02 ～ 0 .10 μg/L)Malachite green , wi thin 4 days , the Malachite green of 0 .02 μg/L has a slight effect on Dicr ateria , and in the concent rat ions ≥0 .04 μg/ L , with concentr at ion of Malachi te green incre asing , the growth rate , content of chlorophylla , carotene and protein of Dicr ater ia wer e r educed mar kedly .Tempera tur e has an evident effect on toxici ty of Malachi te green , the higher the tempe rature is , the gre ater the toxicity will become .