Biodegradable poly(butylene succinate-co-ethylene glycol) (PBSG)/multiwalled carbon nanotube (MWCNT) nanocomposites were successfully prepared through physical blending and silication between PBSG and acyl aminopropyltriethoxysilane functionalized multiwalled carbon nanotube (MWCNT-APTES). Nuclear magnetic resonance (NMR) spectra observations revealed that the PBSG chains were covalently attached to the MWCNT-APTES by hydrolysis. PBSG/MWCNT-APTES nanocomposites after hydrolysis showed excellent interfacial compatibility between PBSG and MWCNT-APTES, which was helpful for the dispersion of MWCNT in the PBSG matrix. The incorporation of MWCNT-APTES accelerated the crystallization of PBSG in the nanocomposites for both approaches of physical blending and hydrolysis due to the heterogeneous nucleation effect of MWCNT while the crystal structure of PBSG was remained. Furthermore, the crystallization rate of PBSG in PBSG/MWCNT-APTES nanocomposites after hydrolysis was slower than that in the nanocomposite by physical blend. The tensile strength and modulus of the nanocomposites increased about 6% and 11% with the addition of only 1 wt% MWCNT-APTES compared with that of neat PBSG, and was larger for the PBSG/MWCNT-APTES nanocomposites after hydrolysis. POLYM. ENG. SCI., 52:2506-2517, 2012. (C) 2012 Society of Plastics Engineers