Thermodynamic behaviors of ternary system (1,2-propanediol (1,2-PG) + 1,3-butanediol (1,3-BD) + 1,4-butanediol (1,4-BD)) were studied in this paper. Vapor-liquid equilibria (VLE) data of systems (1,2-PG + 1,3-BD), (1,2-PG + 1,4-BD), (1,3-BD + 1,4-BD), and (1,2-PG + 1,3-BD + 1,4-BD) were measured at 101.3 kPa. The binary interactive parameters were obtained by regressed the binary VLE data with different models. The results have shown that the Wilson model, the NRTL model and the UNIQUAC model are suitable to describe the ternary system, but the UNIFAC model is not appropriate; the residue curve map of the ternary system was obtained on the basis of the binary interactive parameters. Finally, the design and optimization of the two-column sequence distillation process were completed for separation of the ternary system. Under the optimized conditions, product amounts of 1,2-PG, 1,3-BD, and 1,4-BD can be up to 0.98, 0.90, and 0.98, respectively, after separation.