A thermoplastic starch was prepared by melting processing method using glycerol as a plasticizer and pullulan as an adhesion reinforcing agent.Edible film was prepared by using extrusion blow molding.The effect of glycerol on rheological behavior,glass-transition temperature,enthalpy of phase change and microstructure was investigated.The effect of ambient humidity on mechanical property and thermal stability were studied.The result showed that glycerol can improve the rheological behavior and microstructure of the thermoplastic starch,reduce the glass-transition temperature and enthalpy of phase change.The edible film was suitable under 40% ambient humidity.Under this humidity,with 28% glycerin,the portrait tensile strength of the edible starch film was 5.26 MPa,portrait elongation at break was 137.9 %;transverse tensile strength was 4.92 MPa,transverse elongation at break was 118.0%.