Abstract: Traditional plate culture method can not fully reflect the microbial genetic information in microbiological fermentation bed,so obtaining high quality DNA is necessary to study microbial community structure in fermentation bed.In this research we designed and compared six extraction methods for bedding microbial DNA from fermentation bed,mainly in evaluating concentration and purification of extracted DNA.Results indicated that the kit methods have high pertinence,without specific bedding material microorganism DNA extraction kit,the use of excrement,soil and silt kit did not achieve good results.Simply applying SDS or CTAB methods could not effectively eliminate the pollution of humic acid and remove the complex proteins;so that,the ratio of A260 to A280 of the DNA was lower than 1.5 and no result obtained by PCR amplification.Comparatively,in SDS-CTAB method,using 10% PEG8000 in precipitation obtained the DNA with good integrity and high purity,the concentration of DNA was more than 200 ngL-1,the ratio of A260 to A280 was about 1.8,and the PCR amplified targeted the DNA.Results indicated that the SDS-CTAB was an efficient and reliable method for DNA extraction from microbiological fermentation bed and it would be also conducive to the research of molecular ecology.