Abstract: The growth ability of 50 Lactic acid bacteria strains isolated from the traditional fermented food in Inner Mongolia were screened in the sugar- free LB medium,and acid producing capability and protein decomposition capability were measured as the goal value in the red bean milk. Then the protein decomposition capability of selected strain was tamed gradually. The results showed that the three strains( S2- 4,Sc8- 1 and NM- 6) were screened out with good growth ability,and one of the best strain NM- 6 was selected by measuring protein decomposition capability in the red bean milk,and its total acidity and the free amino nitrogen content at 37 ℃ for48 h were 0.27% and 1.215 mmol / L,respectively.After taming,the total acidity and the free amino nitrogen content of strain NM-6 were improved by 59.3% and 25.3%.The tamed strain had better adaptability in the red bean milk,at the same time the higher strain activity was helpful to improve the quality of soymilk yoghurt products.