在0.14mol·dm~(-3)H_2SO_4介质中,PO_4~(3-),MoO_4~(2-)与罗丹明S形成磷钼杂多酸-罗丹明S三元缔合物,在610nm处产生一灵敏的共振散射(即瑞利散射)光谱峰,磷浓度在0.2～20μg·dm~(-3)范围内与共振散射光强度呈良好线性关系.实验结果表明,本法具有灵敏度高、选择性好等特点,用于水和茶叶试样中磷酸根的测定,结果与示波极谱法的测定结果一致. In 0.14mol · dm -3 H_2SO_4 medium, PO_4 ~ (3 -), MoO_4 ~ (2-) and Rhodamine S form phosphomolybdic heteropoly-rhodamine S ternary association at 610nm (Rayleigh scattering) spectra peaks with a good linear relationship between the concentration of phosphorus and the intensity of resonance light scattering in the range of 0.2 ~ 20μg · dm ~ (-3) .The experimental results show that this method has the advantages of high sensitivity, Good selectivity and other characteristics for the determination of phosphate in water and tea samples, the results consistent with the determination of oscillopolarography.