Abstract: Objective: To verify the effect of the α- amy( α- amylase gene) used in Leuconostoc mesenteroides,construction of recombined plasmid and triparental mating system in Leuconostoc mesenteroides were performed.Methods: The recombined plasmid p CW7,containing α- amy,was constructed based on E. coli- Leuconostoc shuttle vectors p CW4. 6- Phosphoglucose dehydrogenase gene( g6ph) expression cassettes from Leuconostoc mesenteroides ATCC8293 was cloned into p CW7 and introduced into Leuconostoc mesenteroides by triparental mating. Results: Compared with the wild type,the recombination strain increased 7% yield of mannitol. The recombinant can be successfully selected by α- amylase gene markers.Conclusion: It showed the practicability ofα- amylase gene markers used in improving the gene expression of Leuconostoc mesenteroides.