Ca-GMMT suspension was prepared by calcium-based montmorillonite (Ca-MMT) and glycerol in a constant temperature oil bath. The composite thermoplastic starch (TPS) was prepared by Ca-GMMT, glycerol and starch in a certain proportion under high temperature hot shear of twin screw extruder. The effect of Ca-GMMT filling amount on the properties of TPS materials was analyzed. The results show that the addition of Ca-GMMT can greatly improve the tensile strength of TPS materials. The addition of Ca-GMMT does not change the crystallization of TPS. The addition of Ca-GMMT improves the thermal stability of TPS materials. When the addition amount of Ca-GMMT is 8%, the initial thermal decomposition temperature and the maximum thermal decomposition rate temperature of TPS increase from 288.6 ℃ and 312.2 ℃ of TPS to 304.3 ℃ and 321.8 ℃, respectively. The amylopectin in corn starch will enter the lamellar structure of MMT to form a tighter structure, but the addition of too much Ca-GMMT will form a agglomerated structure, which will affect the compatibility of the composites. The addition of Ca-GMMT can greatly improve the hydrophilicity of TPS materials, and when the addition of Ca-GMMT reaches 8%, the TPS material changed from hydrophilic to hydrophobic.