PVA was precured with glycerin/diethanolamine/sorbitol as compounded plasticizer and plasticized on mixer, and then the PVA composites film was prepared on vulcanizer. The melting behavior, surface morphology and mechanical properties of the PVA composites were characterized with DSC, SEM and tensile testing machine. The results showed that there was a great collaborative plasticizing effect when glycerol, diethanolamine and sorbitol were mixed at molar ratio of 1:1:1 as compounded plasticizer, which significantly reduced the melting temperature of PVA. The optimum processing parameters were as follows: precuring at 50 ℃ for 12 h; and mixing with 30 r/min at 180 ℃ for 20 min. The melting point of PVA composites was at 161.6 ℃ when loaded with 25 wt% compounded plasticizer, dropping 33.4 ℃ compared to melting point of the pure PVA.