Seed yield and oil content are two important agricultural characteristics in oil crops breeding and much functional gene research is being concentrated on elevating these properties.In this study, by differential gene expression analyses between rapeseed lines (zy036 and 51070) which exhibit different levels of seed oil production, BnGRF2 (Brassica napus growth regulating factor 2 like gene) was identified in high oil-producing line zy036.To elucidate the possible roles of BnGRF2 on seed oil production, we isolated the eDNA sequences of rapeseed GRF2 gene.Blastn result showed rapeseed contained BnGRF2a/2b which located in A genome (A1 and A3) or C genome (C1 and C6), respectively and the dominant expressed gene BnGRF2a was chosen for transgenic research.Analysis of 35S-BnGRF2a transgenic Arabidopsis showed that over-expressed BnGRF2a resulted in increasing seed oil production over 50%.Moreover, BnGRF2a also induced over 20% enlargement in extended leaves and over 40% improvement in photosynthetic efficiency because of increasing in chlorophyll content.Furthermore, transcriptome analyses indicated some genes associated with cell proliferation, photosynthesis and oil synthesis were upregulated, which revealed that cell number and plant photosynthesis contributed to the increased seed weight and oil content.Because of less efficient self-fertilization induced by longer pistil in 35S-BnGRF2a transgenie line, Napin-BnGRF2a transgenic lines were further used to identify the function of BnGRF2 and the results showed seed oil production also could increase over 40% compared to WT control.Our results suggest that improvement to economically-important characteristics in oil crops may be achieved by manipulation of GRF2 expression level.