Two kinds of homopolyesters (polybutylene succinate, polybutylene succinate) and four kinds of poly (butylene succinate -co- suberic acid) copolyesters were synthesized using 1,4- butanediol and different proportions of succinic acid and suberic acid as raw materials. The molecular structure, thermal properties, crystallization properties and mechanical properties of the copolyesters were characterized by attenuated total reflection Fourier transform infrared spectrometer, nuclear magnetic resonance spectrometer, differential scanning calorimeter, X-ray diffractometer and thermogravimetric analyzer. The results show that when 60% suberic acid unit was introduced, the copolyester has the lowest melting point, the lowest crystallinity, the higher elongation at break and the complete degradation after 8 h, and the mechanical properties of the copolyester become more excellent.