Abstract: This paper reviews the properties,distribution of legume lectins,their genes and expression. In recent years,molecular interaction between host legume plants and rhizobial bacteria implies that the factor of recognizing rhizobia is the lectin on the roots of host plants. After the lectin gene is transferred from one type of legume into another, the latter could be finally infected and nodulated by the rhizobial bacteria that originally only harbor in the former legume. From this fact, crop scientists point out the possibility that the rhizobial bacteria might be extended into non_legume host plants,especially cereal plants for their symbiosis.