Twelve ssDNA aptamers specific for a novel recombinant anti-neuroexcitation peptide (ANEPIII) were identified using the SELEX method from a 79-nucleotide ssDNA pool to purify ANEPIII in a more efficient way. To further understand the binding modes between ssDNA and ANEPIII, fully flexible dinucleotides were docked onto the homology-modeled ANEPIII structure. AutoDocking identified favorable binding sites on ANEPIII for nucleotides, which was valuable for designing more potent ligands.