A series of novel biodegradable poly(butylene succinate-co-1,3-propanediol succinate) [P(BS-co-DO)] were synthesized by melt polycondensation from succinic acid with 1,4-butanediol and 1,3-propanediol. Their chemical structures were identified by FT-IR and 1H-NMR. The effect of 1,3-propanediol amount on the relative molecular weight, thermal properties, crystallinity, mechanical properties, light transmittance and biodegradation of the copolyester were studied. The results showed that the relative molecular weight, Tm and crystallinity decreased with the increase of 1,3-propanediol content. Compared with PBS, the thermal properties, flexibility, elongation at break and light transmittance of the copolyester containing 1,3-propanediol were improved. Degradation experiments showed that the degradation rates of copolymers increased with the increase of 1,3-propanediol content.