The invention provides a triarylamine compound, a preparation method thereof and an organic light-emitting device, which relate to the technical field of organic photoelectric materials. The triarylamine compound has an aliphatic ring on benzene or 9-phenyl of fluorenyl, the aliphatic ring has electron donating ability relative to aryl, the electron donating ability of the compound is further enhanced, and the triarylamine compound has excellent steric configuration, effectively controls the crystallinity of a material, and has good thermal stability. The light-emitting efficiency and the service life of the organic light-emitting device can be improved; the driving voltage of the device is reduced; and the triarylamine compound provided by the invention is applied to the organic light-emitting device as a covering layer material, so that the light-emitting efficiency of the organic light-emitting device can be improved, and meanwhile, the service life of the device can also be prolonged. The triarylamine compound is simple to synthesize and easy to operate, and can be widely applied to the fields of panel display, lighting sources, organic solar cells, organic photoreceptors or organic thin film transistors and the like.