Abstract: Mature embryos of wheat as explants have many advantages for transformation.They can overcome some of the immature embryos’ disadvantages,which is difficult to obtain throughout the year and strictly limited by their suitable stage for culture.Mature embryos of wheat from cultivar EM12 in Hubei province and mode variety Bobwhite were used as target materials.The effects of bombardment pressure,bombardment distance,geneticin etc.on mature embryos of wheat by particle bombardment have been optimized in order to obtain a high frequency of plant transformation system.The results show that optimal values of bombardment parameters were found to be a bombardment pressure of 900 psi at a distance of 6 cm for mature embryos.Mature embryos were more sensitive to geneticin G418 than immature embryos,and they had to be grown for longer time before application of the selectant.The optimal selective concentration of G418 for mature embryos is 20-40 mg/L.Under these optimum conditions,the frequency of transformation for mature embryos of wheat was up to 0.3%-0.9%.The transformation system of mature wheat embryos using particle bombardment has been set up preliminarily.