The invention discloses an extraction method for cut tobacco total deoxyribonucleic acid (DNA) of finished product tobacco. The traditional method for extracting DNA by a cetyltrimethyl ammonium bromide (CTAB) method is improved, 70 percent ethanol water solution is adopted in advance for carrying out pre-treatment on samples, the volume of CTAB precipitate buffer liquid is increased, the difficult problem of great DNA extraction difficulty in the cut tobacco of the finished product tobacco is solved, and a set of stable, complete and feasible method is provided for the total DNA extraction of various kinds of cigarettes. The extraction method has the advantages that the DNA precipitate efficiency is improved, and the DNA extraction difficulty is reduced.