The present invention relates to a phase isolation process for biomacromolecule components, after pretreating the substance to be isolated: 1) adding sufficient amount of buffer (one of the compound selected from ammonium sulfate, cesium chloride, sodium sulfate, and ethylenediamine tetraacetic acid) and homogenizing gently to carry out agglutination; 2) adding phase isolation solution (one compound or a mixture of more compound selected from the group consisting of ethanol, isopropyl alcohol, isobutyl alcohol and acetone) and homogenizing gently, centrifuging to form an upper phase and a lower phase to carry out phase isolation; wherein lipid is in the upper phase, protein precipitates in the phase middle, DNA plasmid, viral nucleic acid, mitochondrial DNA are in the lower phase, and total RNA precipitates in the lower phase; genomic DNA precipitates in the lower phase or in the phase middle together with protein. The production yield and purity of isolating components are high in the present invention, providing advantageous condition for purifying these components.