Microula Sikkimensis is a kind of plant only in China. Fatty acid composition of its seed oil was analyzed with a polar PEG-20M fused-silica capillary column GC combined with MS after the seed oil was saponified and methylated. 13 kinds of fatty acid methyl ester (FAMEs) were identified. The major constituents were found to be oleic acid 18.12%, linoleic acid 35.11%, ?-linolenic acid 8.33%, ?-linolenic acid 13.57% and stearidonic acid 1.21%.