The preparation technique of a novel biodegradable cushioning package material that took the Konjac glucomannan(KGM) as the raw material was developed and its properties were investigated. The freeze-drying method was used to prepare the cushioning package material. And the variations of KGM concentration, freezing temperature and freezing time influencing the cell structure and mechanical property were analyzed by scanning electron microscope and compression test. With the increase of the KGM concentration, the porosity of cushioning package material decreased, whereas the aperture, elasticity modulus and yield strength of cushioning package material increased. The densification stage of the material was also brought forward. With the fall of freezing temperature, both the aperture and porosity of cushioning package material decreased, but the elasticity modulus and yield strength increased. The densification stage of the material was also brought forward. Prolonging the freezing time had little effect on the porosity of cushioning package material, and the aperture slightly increased. The mechanical property showed no obvious change, the elasticity modulus and yield strength decreased slightly, and the stage of densification was slightly delayed. When the KGM concentration was 3%, the freezing temperature was -20 °C and the freezing time was 12 h, the minimum cushioning coefficient of about 2.79 and the maximum static stress of 0.156 MPa were obtained. The property of KGM cushioning package material at the concentration of 3% was similar to that of the low density expandable polystyrene, which has the practical application potential.