The paper established a new resonance light scattering method for determining quercetin content in water solution. It was found that in hexamine buffer solution (pH7.50), sodium-dodecyl-benzene-sulfonate-hexadecyl-trimethyl-ammonium-bromide system can enhance the resonance light scattering intensity of quercetin which is in proportion to the content of quercetin in the range of 2.0×10-9 to 5.0×10-5mol/L. The detection limit is 5.0×10-10mol/L.