Abstract: A plant expression vector consisting of PSY gene was constructed and transformed into ginseng callus via Agrobacterium tumefaciens-mediated transformation. PCR and Southern blotting revealed the successful transformation and expression of PSY in the ginseng callus cells. Analysis with thin-layer chromatography (TLC), spectral characterization, as well as high-performance liquid chromatography (HPLC) showed that the amount of b-carotene production was 143 ug.g-1 (dried ginseng callus cells). This provides a good model for improving nutrition in plants by genetic engineering.