Abstract: The use of genetic engineering technology for high oil plant breeding was the one of the hot international plant genetic engineering at current. Through the use of biotechnology to inhibit gene expression or enhance gene expression in the plant, the relevant gene of the controlling crop seed oil was found. Crop seeds store material mainly from protein, fat and carbohydrate, protein and fat constitute over 70% of the dry matter in Oil-seed composition. Research shows that phosphoenopyruvate carboxylase (PEPc) which activity was relevant with protein content and negatively correlated with fat content in crop seeds. To explore PEPc gene how to regulate oil / protein in molecular mechanism, this experiment has set the PEPc gene of RNAi vector up and carried it into Arabidopsis through tube with the method of tube immersion. Then the herbicide resistance of the transformed Arabidopsis screening was measured. In result, positive strains of transgenic plants were obtained through PCR identification. Statistic from transgenic Arabidopsis T2 generation which screened by herbicide resistance showed that it was segregation ratio most with a 3:1 classic genetic ratio. Using gas chromatographic analysis for T3 transgenic plant seed oil content, it was showed that the transgenic seeds can increase oil content. In the salt preliminary experiment which also observed that the transgenic seeds were significantly reduced in resistance salt.