The total lipid contents and fatty acid composition in four strains of marine green algae (Stichococcus bacillaris MACC/C19, Chlorella sp. MACC/C95, MACC/C97 and MACC/C102) cultivated under different light intensities (3000lx, 5000lx and 8000lx) in f/2 medium were determined. One-way analysis of variance showed that light intensity had significant effects on the relative growth rates, eicosapentaenoic acid (EPA, 20∶5(n-3)) and subtotals of polyunsaturated fatty acids (PUFA) contents of 4 strains of green algae (P<0.05). Light intensity had significant effects on the total lipid contents and subtotals of saturated fatty acids (SFA) of C19, C97 and C102 (P<0.05). Light intensity also had significant effect on subtotals of monounsaturated fatty acids (MUFA) of C19, C95 and C102 (P<0.05). The total lipid contents weakly decreased with the increase of light intensity in C19 and C95, however it was significantly increased with the increase of light intensity in C97 and C102. The proportions of EPA decreased with the increase of light intensity in all strains except C19, the proportions of 20∶4(n-6) and subtotals of PUFA in all 4 strains decreased with increasing light intensity. Multiple comparison tests showed that the total lipid content in C19 grown at high light intensity (8000 lx) was lower than those grown at other treatments, but was not significantly different between the treatments of low light intensity (3000 lx) and middle light intensity (5000 lx) (12.9% and 12.7% of the dry weight, respectively). C97 and C102 had the highest total lipid contents (40.6% and 33.3% of the dry weight, respectively) when grown at high light intensity. The proportion of EPA in C19 reached its highest value (12.7% of total fatty acids) when grown at middle light intensity, and the proportions in C97 and C102 of EPA reached their highest values (12.0% and 10.5% of total fatty acids, respectively) when grown at low light intensity. The proportion of EPA in C95 grown at high light intensity was lower than those grown at other treatments. However there was no significant difference between the treatments of low light intensity and middle light intensity (14.0% and 14.7% of total fatty acids, respectively). The subtotals of PUFA in C19 and C95 cultivated at high light intensity were lower than those cultivated at other treatments. However there was no significant difference between the treatments of low light intensity and middle light intensity (19.1%-19.4% and 21.3%-21.3% of total fatty acids, respectively). The subtotals of PUFA in C97 and C102 reached their highest values (19.2% and 189% of total fatty acids, respectively) when light intensity was 3000 lx. The main fatty acids of 4 strains of marine green algae were 14∶0, 16∶0, 16∶1(n-7), 16∶4(n-3), 18∶1(n-9), 18∶3(n-3), 20∶4(n-6) and EPA.