The invention belongs to the technical field of organic photoelectric materials and particularly relates to a transition-metal complex used as a phosphorescent material, a preparation method and application thereof. The transition-metal complex, the preparation method and the application have the beneficial effects that by matching of Z1 and Z2, the wavelength of the emitting light of the materialcan be adjusted in a larger range of wavelength, meanwhile the wavelength of the emitting light can be further accurately adjusted by changing heteroatoms on main ligands, so that an electroluminescent material with predictable luminescent color is obtained; the main ligands have same skeleton structures, large-range adjustment of the wavelength of the emitting light from green to dark red can berealized only by changing the positions of functional groups and the positions and the types of the heteroatoms on the main ligands; the complex prepared by the invention is high in luminescent efficiency, and the preparation methods of the luminescent materials with different colors are same basically and are simple in operation.