Three-dimensional finite element model of impregnated diamond bit was established based on finite element analysis software ANSYS/LS-DYNA and the influence of cutting teeth structure on drilling efficiency was analyzed with the field test verification carrying out; a new method for stress area comparison based on Image-Pro Plus was present. The results show that stress concentration appears for concentric ring cutting teeth structure at the front edge of cutting teeth along the rotation direction in initial drilling stage, while non obvious stress concentration appears for saw teeth bit. But different degrees of stress concentration appear at inner and outer diameter edges near the nozzle part for these two kinds of bits in late drilling stage, which may lead to abnormal wear. The saw cutting teeth bits are more efficient than concentric ring ones, but the bit service life is slightly lower.