To understand the change of lactic acid bacteria during total mixed ration （TMR） silages ensiled process, MRS agar was used to cultivate and separate lactic acid bacteria from fresh brewers grains, soybean curd residue and their TMR silages (stored for 0 day, 14 and 56 days); These cultivable lactic acid bacteria were screened by PCR-DGGE, and then the products were analyzed for bacterial DNA sequences. GenBank database was searched to determine the closest relatives of 16S rDNA sequences to identity them. The results showed that the lactic acid bacteria were different between fresh brewers grains and soybean curd residue; and the predominant lactic acid bacteria species were altered when they were mixed with other materials. There were two species of lactic acid bacteria in both of the two TMR silages in the initial period of fermentation, and one species was the same between the two TMR silages; but five species of lactic acid bacteria were found in the two TMR silages in later fermentation, and four species were the same between the two TMR silages. In conclusion, lactic acid bacteria species tend to be the same, and species types increase in later fermentation when using different food by-products to make TMR silages.［Chinese Journal of Animal Nutrition, 2010，22（6）:1636-1643］