Konjac glucomannan (KGM) and poly (vinyl alcohol) (PVA) were mixed to form gel-like polyelectrolyte solution with glycerol and sorbitol as compound plasticizer, which was used to prepare packaging films via casting and drying. The results show that the tensile strength and elongation at break of the packaging films drop sharply when the blending temperature and blending time exceed 80 °C and 3.5 h. When the mass ratio of sorbitol and glycerol in the compound plasticizer ranges from 1:1 to 1:3, it is beneficial to improve the tensile strength of the packaging films. The microscopic reasons for the change of the tensile properties of the packaging films are mainly caused by diffusion-stop-continuing diffusion—precipitation of low-molecular electrolyte, which makes the system shift from equilibrium-homogeneous state- unbalanced state—heterogeneous state.