Abstract: Taking callus induced from shoot apex explants of potato onion（Allium cepa var. aggregatum Don） as test material, the foreign gene AtWUS genetic transformation was carried out by the agrobacterium-mediated transformation method with potato onion callus.The effects of AtWUS on somatic embryogenesis（SE） of potato onion calluswas studied, in order to develop a high-frequency SE regeneration systemvia over-expressing AtWUS from in potato onion callus.The results showed that overexpression of the AtWUS gene incallus promoted, as the percentage of explants giving rise to embryogenic tissues was significantly higher（×6） when AtWUS gene was over-expressed than in the control.Bipolar somatic embryos resulted 91% complete plant regeneration.RT-PCR analysis showed that AtWUS gene was highly expressed in somatic embryos and transgenic plants.