Abstract: Disclosed is a DNA sequencing method. The DNA sequencing method provided in the present invention comprises the following steps in order: (1) adding a tag sequence at the 3? terminus of the DNA to be sequenced so as to form a DNA to be sequenced including the tag sequence, the nucleotide sequence of said tag sequence being the reverse complement of the nucleotide sequence of the sequencing primer; (2) mixing the DNA to be sequenced including the tag sequence and the sequencing primer so as to form a product having a 5? terminus double strand and a single main strand; (3) after step (2) is completed, the product is mixed separately with dATP, dCTP, dTTP, and dGTP to obtain four systems, each system is separately added to a single-molecule device modified by a DNA polymerase, and electric signals are read. Experiments verify that the method provided in the present invention performs DNA sequencing and has important application value.