A new organic pyridinium dye named as 4-［4-（N，N-diethylamino）-2-hydroxy-styryl］-N-methylpyridinium iodide（DEHSPI）has been synthesized.Its crystal structure was determined by X-ray diffraction.DEHSPI belongs to monoclinic system，C2/c space group，a=3.5970（4）nm，b=1.16270（15）nm，c=2.2081（3）nm，β=114.341（7）°，V=8.4139（18）nm3，Z=8，F（000）=3632，μ=1.536 mm-1，Dc=1.417 g·cm-3，R=0.0501.The structure analyses of DEHSPI and the dye without 2-hydroxyl group revealed that the planarity of cation backbone in DEHSPI was strongly increased by the 2-hydroxyl group.The photophysical properties of the dye in different solvents and a polymer-impregnated sol-gel composite glass were also investigated.The fluorescence intensity in the composite glass with higher concentration increased greatly as compared with that in solution and there was no fluorescence quenching based on the aggregation of molecules in high concentration.The dye had higher stability in the composite glass.