In this study, the plant binary expression vector pBI121 served as the backbone to transform into the BnaLPAT2 overexpression vector (p35S-BnaLPAT2) and the seed-specific expression vector (pNapin-BnaLPAT2) by use of freez-thaw transform method. Analysis of the fatty acids in the seeds of the transgenic plants showed that, compared to wild-type Arabidopsis thaliana, the relative content of seeds oleic acid of progeny plants expressing p35S-BnaLPAT2 decreased by 1.3 and the relative content of linolenic acid (C18∶3) increased by 3.2. The relative content of linoleic acid (C18∶2) was reduced by 0.7; the relative content of seeds oleic acid of progeny plants expressed by pNapin-BnaLPAT2 decreased by 1.29, the relative content of linolenic acid increased by 2.73, and the relative content of linoleic acid increased by 1.04. BnaLPAT2 has a higher affinity for linolenic acid than linoleic acid and oleic acid.