The effects of amphotericin B (150 $mu$g/ml) and cycloheximide (10 $mu$g/ml) on the biosynthesis of phospholipid and their fatty acid composition in chloroplast isolated from Chlorella were analyzed to compare with control. The levels of total lipid, phosphatidylethanolamine (PE), and phosphatidylcholine (PC) in the group treated with antibiotics were decreased. However, the biosynthesis of phosphatidylinositol (PI) was not affected by antibiotics. The major fatty acid in chloroplast envelope was linolenic acid (27.71%) in control and stearic acid (21.59%) in the group treated with amphotericin B. It was showed that the group treated with cycloheximide contained more unsaturated fatty acid than the control.