Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibited higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate (PTT) via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260°C after 1.5 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polyester, polymerized at 260°C, 60 Pa for 2 h, was 0.8950 dL/g and 15 mol/t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester. Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibits higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate (PTT) via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260 ° C after 1.5 h, while the intrinsic viscosity and content of the terminal carboxyl groups were corresponding PTT polyester, polymerized at 260 ° C, 60 Pa for 2 h, was 0.8950 dL / g and 15 mol / t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester.