Hyperbranched polyglycerol (HBPG) of generation three was synthesized by ring-opening multibranching polymerization method using glycerol and glycidol as materials and sodium methoxide as catalyst. Oleic acid was then used to modify HBPG with different content to obtain a series of products named HBPG-X. FT-IR and 1H NMR were employed to characterize structures of HBPG and HBPG-X. Then HBPG-X and commercially available fatliquoring agent SK-70 were used in fatliquoring process of sheep skin garment leather. The results showed that the softness and mechanical properties of all treated leather were increased compared with original leather. HBPG-1 showed best effect on softness of the fatliquored leather which was similar with SK-70.