Abstract: Although mixcolumn transformation of AES algorithm has the best diffusion features，its efficiency of circuit implementation is far different from that of inverse column transformation.By investigating the procedure of AES mixcolumn transformation，a number of new mixcolumn transformations are proposed according to characteristics of circuit implementation，in which encryption and decryption implementation may use the same circuits.While retaining the best diffusion features，the new kind of mixcolumn transformation obtains almost the same cost and efficiency as that in AES.