The present application can provide a nanoparticle, a method for patterning a nanoparticle layer and a light emitting device. When the nanoparticle provided by the present application is adopted for manufacturing a light emitting layer of the light emitting device, a cross-linking reaction occurs among first ligands of adjacent nanoparticles under irradiation of ultraviolet light, and the cross-linked nanoparticles may be firmly connected to a front film layer of the light emitting layer, so that when a developing solution is adopted for developing treatment, the cross-linked nanoparticles are not insoluble in the developing solution and are retained while non-cross-linked nanoparticles are dissolved in the developing solution and are separated from the front film layer to be removed, therefore completing patterning of the nanoparticle layer.