Fviii fusion protein conjugate having extended half-life and use thereof

A conjugate of a coagulation factor VIII-Fc fusion protein and polyethylene glycol (PEG), wherein the coagulation factor VIII-Fc fusion protein comprises an active moiety of the coagulation factor VIII (FVIII) and an Fc fragment, the active moiety of the coagulation factor VIII (FVIII) is directly connected to the Fc fragment or indirectly linked to the Fc fragment through a linker to form the fusion protein, the conjugate is modified with PEG at an average PEG number of 3-8, 3-7, 3-6, 4-8, 4-7, 4-6 or 4.2-5.1, preferably 4.2-5.1, and the average PEG number of modification is the molar ratio of the PEG to the fusion protein;

• wherein, a modifier for PEG modification has a structure represented by formula (2):
• wherein, 0≤m2≤6, preferably, m2 is 2;
• 0≤m3≤6, preferably, m3 is 1;
• mPEG-represents a methoxy mono-capped polyethylene glycol group;
• and
• preferably, the PEG has a molecular weight of 30 kD-50 kD, preferably 40 kD.