The invention provides a stripping method for a two-dimensional B3N4 nanomaterial, a dispersant, a dispersing method and an application of the dispersant. A boron nitride dispersant comprises a polyaniline conducting polymer which can be combined with boron nitride under a physical action to stably disperse boron nitride into a dispersion medium. The polyaniline conducting polymer with low cost is used as the boron nitride dispersant, and the dispersant is simply mixed with boron nitride in the dispersion medium, so that the dispersion degree and dispersion stability of boron nitride and particularly a two-dimensional boron nitride nanomaterial in the dispersion medium can be greatly improved due to the mutual physical action of the dispersant and boron nitride; a boron nitride nanosheet can also be obtained by using a simple liquid-phase stripping method by virtue of the polyaniline conducting polymer, and the physical structure and chemical property of boron nitride cannot be damaged; in addition, the dispersion medium applied to boron nitride dispersion or boron nitride nanosheet stripping can be recycled, so that the cost can be reduced, the emission of organic matters is reduced, and large-scale implementation can be favorably realized.