Abstract: Analysis of free amino acids shows that the wheat callus can actively absorbe the L-proline in the medium and accumlate it in vivo, and also transform it into other amino acids. The formation of tracheary system in the long term subculture of wheat callus is due to the increase of phenlpropanoid metabolism according to the results of increase of phenylalanine ammonia lyase(PAL)activity. In this paper the roles of L-proline in wheat callus culture are discussed on the results of long-term subculture growth on the media added other several amino acids and relevant reports in this aspect.