Abstract: The progress of nucleic acid molecular “Light Switch” and DNAwas reviewed in this paper, which is obtained with ultraviolet absorption spectrum, fluoremetry, NMR, Tm and linear dicroism(LD), etc . The mechanism of fluorescence enhancement of molecular “Light Switch” by DNAand the charge transfer reaction between Ru(Ⅱ) and Rh(Ⅱ) are reported. It also describes the application of nucleic acid molecular “Light Switch” in sequence analysis, quantitative analysis of DNA, determination of c cm and detection of solvent polarity. The possible development of the nucleic acid molecular “Light Switch” is addressed.

Key words: Nucleic acid recognition, Nucleic acid molecular “Light Switch”, Intercalate binding, Charge transfer reaction