Biomass sodium alginate (SA) and biomass-derived ether tetrahydrofuran (THF) have drawn considerable attention due to their sustainability and bio-renewability. In this paper, the novel acylated sodium alginate-gpolytetrahydrofuran graft copolymers (ASA-g-PTHF) with various PTHF branches (M-n,M- PTHF=600-4800 g/mol, G(N)=3-20 per 1000 SA monosaccharide) could be successfully synthesized by combination of THF living cationic ring-opening polymerization with grafting-onto method. The microphase separation of ASA-g-PTHF graft copolymer formed via self-assembly from two kinds of segments in backbone and side chains and was emphasized by thermal annealing, leading to a remarkable increase in water contact angle on polymer surface even by 38.4 degrees. The hydrophilicity and crystallization behavior of ASA-g-PTHF can be decreased with increasing M-n,M- PTHF and G(N), which confine the crystallization of graft copolymer. ASA-g-PTHF microspheres (similar to 1 mu m) loaded with ibuprofen shows pH sensitivity and reach 100% of drug-release at pH=7.4 within 30 h. ASA-g-PTHF exhibits resistance to bovine serum albumin adsorption and its composite with small-scaled silver nanoparticles (AgNPs,< 2.6 wt%, 5-15 nm) generated in-situ behaves good antibacterial performance against E. coli and S. aureus. The ASA-g-PTHF would contribute to the better utilization of biomass and has promising for biomedical applications.