Abstract: The Lagerstroemia indica was a important flower species in summer, which was widely cultivated in our country. In order to develop and use of L. indica seed oil, cold pressed method was used to extract the oil from the L. indica seed, the fatty acids composition of the seed oil of L. indica Amabilis Group、L. indica Rubra Group and L. indica Alba Group were determined by GC/MS. The results showed that different varieties of L. indica seed oil contained the same 17 kinds of fatty acids, there were differences between the fatty acid content of different variety groups. The total unsaturated fatty acids content of L. indica Amabilis Group was highest, which content was 86.57%; the total saturated fatty acid content of L. indica Amabilis Group was lowest, which content was 13.05%. The main components of the unsaturated fatty acid was oleic acid and linoleic acid. The linoleic acid content of L. indica Amabilis Group、L. indica Rubra Group and L. indica Alba Group were 70.91%、71.62% and 70.91% respectively. The odd number carbon fatty acids which had antitumor activity was determined out from L. indica seed oil. It indicated that L. indica seed oil was a health oil that worth to develop.