Abstract：The technical pure azo dye FRL was purified by recrystallization with the solvent composed of ethanol and water whose volume ratio is 1∶1. The azo dye FRLP was obtained by coincidence reaction with phen after reoxidation reaction by purified FRL and sodium nitrite, which can be cooperated with Cu2+. And at room temperature the UV-Vis spectrum of FRLP-Cu2+ was studied. The form of the complex was confirmed by successive changing equal number of moles, which is in the B-R solution from pH 6 to pH 9, and the ratio of the complex(Cu2+∶FRLP) is 1∶2. In the B-R solution(pH 8.8) the mol absorption parameter of the complex is ε590 nm＝9.5×104 L·mol-1·cm-1,and the apparent stable constant is K＝5.12×1012. The property of ultraviolet band spectrum of FRLP-Cu2+ was studied, showing that the aqueous solution of the complex can absorb the ultraviolet radiation strongly from 200 nm to 305 nm. The complex mixing with PVAL can also absorb ultraviolet radiation strongly. At the maxmium absorption wavelength in the visible zone and laid parallelly with the optical axis, the transmission of the single slice is 45%-50%, the transmission of two slices laid vertically is zero from 200 nm to 325 nm, and the averaged transmission from 325 nm to 400 nm is 10%.
