Abstract: The present experiment was conducted to assess DNA extraction method of freezing-thawing and methods combined freezing-thawing and CATB. Results showed that the methods combination of freezing-thawing and CATB could smash cell wall of varieties of micro-organisms including bacteria and Fungus. DNA extraction was stable by this technique and DNA fragments were large enough to be applied in follow-up research. It could be concluded that freezing-thawing and CATB methods combination could extract the total rumen microbial DNA.