The project was conducted to study the distribution of lactic acid bacteria population in silage corn in different regions of Inner Mongolia. Microbial genome DNA in silage was carried out by benzyl chloride method, and target fragments were amplified with P2f and P3r as primers, then distribution of lactic acid bacteria population was analysed by denature gradient gel electrophoresis (PCR-DGGE) method. The results showed that DGGE profiles of lactic acid bacteria exhibited high homology in silage from 9 pastures of 3 regions. The majority of sequence standed for lactic acid bacteria; among lactic acid bacteria LAB sequence, content of ?-Lactobacillus ranked on the top of the list. Besides, it was found that there were 3 coccus (Lactococcus, Weissella and Leuconostoc) alive in the silages for more than half a year. In addition, the similarity between band 10 and ?-Acetobacter reached to 94%, and similarity between band 4 and ?-Lactobacillus was 93%; but the two strains could not be identified to the level of specie, which belonged to strains without culture or sequence.［Chinese Journal of Animal Nutrition, 2009，21(6):974-981］