In order to provide basic theory for the novel structural design of earth auger, the holedigging experiments and then the static and modal finite element analysis were carried out, combining the theory and experiment. The vertical resistance and torque on the drill were obtained from the digging experiments, which were applied on the 3D drill physical model. And the finite element method was used in this simulative study. The static simulative results showed that the largest Mises stress value was 111.0 MPa, locating at the inwall of the bolt hole connecting the main cutting blade and its shelf, and the largest deforming displacement value was 0.68 mm, locating at the out corner of main cutting blade. The first six natural frequencies and modes were provided by model analysis, and five modes of the six will increase the vibration of the drill, except for the third one, which is good for the decrease of resistance and stress concentration.