After series of screening a marine chlorella was selected for further study. In L₁ seawater medium the chlorophyll fluorescence induction dynamics of Chlorella sp. under different environmental conditions was analyzed after 48 hours. The results showed that the chlorophyll fluorescence induction dynamics parameters such as maximum quantum yield (Fv/Fm), per excited cross section (CS) for trapping (TRo/CSo), electron transport (ETo/CSo), and density of active reaction centers (RC/CSo) of Chlorella sp. were affected by light intensity, temperature, and the concentration of nitrogen and phosphorus. The chlorophyll fluorescence parameters was increased with certain environmental factors, but inhibited when the environmental factors exceeded the limits. The best condition for chlorophyll fluorescence induction dynamics parameters of Chlorella was composed of 150μmol · m^-2 · s^-1 light intensity, 18℃ temperature, 8.8mmol/L NaNO₃, and 0.145mmol/L NaH₂PO₄ · H₂O. The net photosynthetic oxygen evolution rate of Chlorella sp. under different environmental conditions was examined, and the results were consistent with that of the chlorophyll fluorescence induction dynamics. Based on the formula of L₁ medium, the optimal culture media of Chlorella sp. was determined (8.8mmol/L (NH₂)₂CO, 0.145mmol/L NaH₂PO₄ · H₂O, 150μmol · m^-2 · s^-1 light intensity, 18℃ temperature). Under the optimized culture conditions, the cell density of Chlorella sp. was significantly higher than the conditions before optimization, the cell density reached 6.3×10⁷/mL after 10 days culture, and the density was increased by 24%. The total lipid and fatty acid of Chlorella sp. were increased by 16.8% and 66.6% respectively. In addition, the cell growth rate and the accumulation of fatty acids of Chlorella sp. were improved by addition of exogenous citric acid (the optimal concentration was 0.06mmol · L^-1 · d^-1). Statistics analysis showed that the fatty acids content of Chlorella sp. was positively correlated with citric acid (P<0.5). Under the conditions of optimized light intensity, temperature and NaH₂PO₄ · H₂O concentration, the growth rate, total lipid and fatty acid contents of Chlorella sp. with different nitrogen source (NaNO₃, (NH₂)₂CO, NH₄Cl, the concentrations were all 8.8 mmol/L) were examined and the results showed that the cell density of Chlorella sp. cultured in three types of nitrogen source all reached the highest after 10 days culture. The cell density of Chlorella sp. cultured in the medium of (NH₂)₂CO as nitrogen source was 1.85 times that of NaNO₃ as nitrogen source, and 1.5 times that of NH₄Cl as nitrogen source. The fatty acid and total lipid contents of Chlorella sp. under different nitrogen source conditions were measured, and the results showed that the fatty acid content of Chlorella sp. cultured in the medium of (NH₂)₂CO as nitrogen source was the highest, accounting for 13.3 percent of the dry weight, and being 2.7 times that of NaNO₃ as nitrogen source, and 1.36 times that of NH₄Cl as nitrogen source. The total lipid content of Chlorella sp. cultured in the medium of (NH₂)₂CO as nitrogen source accounted for 58.6 percent of the dry weight, slightly lower than the NH₄Cl as nitrogen source, but much higher than the NaNO₃ as nitrogen source. The (NH₂)₂CO (concentration 8.8 mmol/L) was the best nitrogen source for the culture of Chlorella sp.. In summary, the selected Chlorella sp. has many advantages such as fast growth, easy culture and high oil production, and can be used as a good material for bio-energy research and also for the development and utilization of marine microalgae.