Abstract: The effect of temperature, illumination intensity, salinity, pH, and nutrients on growth and reproduction of Isochrysis 0898 sp was studied under the experimental conditions. It was found that the adaptive water temperature ranged between 10~35 ℃ with the optimal temperature of 20～25 ℃. The adaptive illumination intensity was 500～10000 lx with optimal value of 3500~10000 lx. The range of adaptive salinity was 5～70, and the optimal salinity was 30. The range of adaptive pH was 3~9 with the optimal pH 7~8. A better culture solution is made of the following substances in the natural sea water: NaNO₃—N 10 g•m^-3, NaH₂PO₄—P 1 g•m^-3, FeC₆H₅O₇—Fe 0.1 g•m^-3, Vitamin B₁1g•m^-3, and Vitamin B₁₂ 0.05 g•m^-3.