A fibroblast growth factor 21 (FGF21) variant, further to a FGF21 variant fusion protein, a protein multimer, and use thereof are provided. The FGF21 variant, fusion protein and protein multimer can significantly improve the binding ability with the target and can be used to treat metabolic diseases.本發明涉及一種FGF21變體,進一步涉及FGF21變體融合蛋白、蛋白質多聚體及其應用。本發明所述的FGF21變體、融合蛋白及蛋白質多聚體能夠顯著提高與標靶的結合力,並能夠用於治療代謝性疾病。