Nannochloropsis oculata is a kind of important economic algae. A series of ecological factors of N. oculata were studied, including temperature, illuminations, salinities and carbon dioxide concentration.The orthogonal designing method was used to study the effects of N, P, Fe on the growth of N. oculata. It was shown that the suitable environmental conditions for N. oculata are as follows: The species grows at the temperature of 0-30℃, and the highest growth occurred at about 20℃. The best illumination intensity may be from 5 000 lx to 7 000 lx. And the higher illumination intensity was better. The algae has a normal growth in medium with salinity ranging from 13.7-33.4, the best salinity was 26.9. And it prefers NaHCO₃ to free carbonic dioxide. When the nitrogen concentration is 10 μmol·L^-1, the phosphorus concentration is 2 μmol·L^-1 and the ferrous concentration is 0.2 μmol·L^-1, the N. oculata has its highest growth rate.