The invention relates to a preparation method of keratin complex fiber, which comprises the following steps: 1, mixing the dried keratin powder, high polymer for fiber forming, ionic liquid and the like, and mechanically stirring and dissolving to obtain a keratin complex solution at certain temperature; (2) preparing a keratin complex fiber by using a dry jet wet spinning process. According to the invention, the keratin used according to the invention comes from leftovers of processing industry such as chicken feather, drake feather, goose feather and wool, and as for the recycle of the waste, on one hand, the economic benefit is increased, on the other hand, the environment pollution can be reduced. The selected high polymer for fiber forming and keratin can dissolve together in the same ionic liquid, so that the characteristics of high efficiency, simpleness and convenience can be achieved. Compared with the pure keratin fiber, the strength and elongation at break of the spun regenerated keratin can be improved greatly, the practical use value can be increased; the keratin complex fiber has wide potential application in the fields of clothing, wig, tissue engineering and the like. In addition, the solvent ionic liquid can be completely recycled, can not pollute the environment and has the meaning of sustainable development.