A linker peptide for constructing a fusion protein. The linker peptide comprises a flexible peptide and a rigid peptide. The flexible peptide consists of one or more flexible units. The rigid peptide consists of one or more rigid units. The flexible unit comprises two or more amino acid residues selected from Gly, Ser, Ala, and Thr. The rigid unit comprises a human chorionic gonadotropin β-subunit carboxy-terminal peptide (CTP) bearing a plurality of glycosylation sites. The linker peptide can more effectively eliminate mutual steric hindrance of two fusion molecules, decreasing a reduction/loss of polymerization or activity resulting from improper folding of an active protein or a conformational change. On the other hand, the negatively charged, highly sialylated CTP can resist renal clearance, further prolonging a half-life of a fused molecule and enhancing bioavailability of a fused protein. Furthermore, a protective effect of a glycosylated side chain CTP can lower the protease sensitivity of the linker peptide, making a linker region of the fusion protein less degradable.
