Potato is a kind of vegetable whose damage cannot be easily observed. Regarding to this property, a method to determine the critical damage dropping height is proposed. At first, quasi-static compression is conducted to the potato, and then the compressive deformation is obtained. Meanwhile, with the experiment to obtain the potato’s dropping signal, the mathematical model reflecting relation between dropping height and dropping deformation can be obtained. The critical damage dropping height is gained from the model with previous compressive deformation, that is 38 cm.