In the study of thermal distortion of resonator mirrors under high-power laser irradiation, the high reflective coatings are usually ignored. The thermal distortion distributions of resonator mirrors with high reflectivity fixed in different ways are analyzed by finite element analysis software ANSYS under the specific laser irradiation (absorbed power of 250 W, outer radius of 4 cm, inner radius of 2 cm, co-axial annular beam, 30 s). The effects of two different high reflective coatings and the field distribution of standing wave inside the coatings are considered, and the results are further compared and analyzed with the usual approximate method that the high reflective dielectric coatings are ignored. The results show that, the difference of thermal deformations among the three situations, i.e., considering two different high reflective coatings and ignoring the high reflective coatings, is relatively small when the resonator mirror is clamped radially. However, the difference becomes obvious when the resonator mirror is clamped axially and the center of the mirror can be convex, concave and flat. If the resonator mirror is fixed by three cones, though the center of the mirror can be relatively flat, there is still obvious difference among the three situations in the irradiation zone of the annular laser. Consequently, the contribution of the standing wave inside the high reflective coatings to the thermal distortion of resonator mirrors cannot be ignored in some applications.