The kit is suitable for extracting total DNA of high-purity from fresh or frozen animal tissues, cells, blood, bacteria and other samples. This product can be used to obtain a DNA fragment up to 50 kb. The purification process does not require the use of toxic solvents such as phenol or chloroform and does not require ethanol precipitation.The optimized buffer system allows the DNA after lysis to be efficiently and specifically bound to the silica matrix column. The inhibitors of PCR and other enzymatic reactions can be effectively removed by two-step washings, and finally high-purity DNA is obtained by elution with a low-salt buffer or water. The purified DNA can be directly used in downstream experiments such as enzyme digestion, PCR, Real-Time PCR, library construction, Southern Blot, and molecular markers.