The invention belongs to the technical field of an organic optoelectronic material, and particularly relates to a transition metal complex used as a phosphor material, and a preparation method and application thereof. Through the matching of Z1, Z2 and Z3, the emission light wavelength of the material can be regulated in a large wavelength range; meanwhile, main ligands further and finely regulatethe wavelength of the emitting light through heteroatoms, thus realizing the important value on luminous materials with various wavelengths. The prepared complex has high luminous efficacy; the wavelength of the emission light is adjustable in a large range. The main ligands of the complex have the same framework structure. By changing the functional group positions, positions of the hetero atomson the main ligands and the types of the hetero atoms, the large-range regulation of the emitting light wavelength from the emitting light wavelength to dark red light can be realized. In addition, the preparation methods of luminous materials of different colors are basically identical; the operation is simple.