Based on a tight-binding disordered model describing a single electron band, we establish a one-dimensional disordered binary DNA model, and calculate the density of electronic states，the localization property of electronic wave-function and the localization length of a DNA sequence with 2×104 nucleotide base pairs. We also investigate the effect of composition of nucleotide base pairs, the degree of disorder of the energy base pairs on the localization length. The results indicate that the electronic states of DNA sequence are localized due to the compositional disorder of nucleotide base pairs and the energy disorder of the lattices, and the localization length is dependent on the composition of nucleotide base pairs and the disorder degree of lattices energy.