Method for extracting nucleic acid from biological sample

The invention provides a method for extracting nucleic acid from a biological sample. The method for extracting nucleic acid from biological samples comprises the following steps: cracking the biological sample to obtain a cracking product containing nucleic acid; and separating nucleic acid from the cracking product. The cracking of the biological sample further comprises: digesting the biological sample by a mixture containing lysozyme, helicase, and lyticase; centrifuging the digested product, collecting the precipitate; cracking the precipitate by a lysate to obtain the cracking product containing nucleic acid. The method can effectively extract nucleic acid from a biological sample.