This invention presents a set of methods to extract DNA, RNA and protein simultaneously from biomaterials by reagents with high pH. DNA and RNA can be extracted from a upper aqueous phase simultaneously either together as a DNA and RNA mixture or separated DNA and RNA. Protein can be extracted from lower organic phase. The DNA and RNA mixture can be used either as DNA or RNA directly depending on applications without further separation, or as resource for the separated DNA and RNA that can be selected from the DNA and RNA mixture by selective precipitation and/or by selective enzyme digestions. This invention provides the choice of extraction either of DNA and RNA mixture or of separated DNA and RNA simultaneously, as well as extraction of protein from the same piece of biomaterials in high quality, which is very critical for biomaterials with limited resource, such as clinical specimens.