DNA recognition of the transcription factors involves both general chemical rules and specific stereochemical rules. Recognition helice of transcription factor families binds to DNA, positing at a major groove. Pairing between the “residues line” of recognition helix and “base line” of base positions makes full fitting, usually involving 3 turns of α-helix and 3～5 base pairs.The binding geometry determined by interaction of the residues and bases in recognition area is indicated in the stereochemical chart, which shows recognition specificity. Stereochemical rules of DNA recognition by transcription factor family are summarized at bases of the chart.