Reinforcing rib structure in the aluminum heating-plate automatic casting system was modeled by ANSYS, the static and dynamical problems were studied. Deformation and stress were calculated by static analysis, the front ten orders inherent frequency, critical rotating-speed and vibration modes were analyzed by modal analysis technology, vibration amplitude responses were obtained by harmonic response analysis. The maximum deformation value of reinforcing rib structure was less than 2mm (irrespective of the structure self-weight); the maximum equivalent stress was about 64.8MPa. It showed that the reinforcing rib structure could effectively avoid the resonance region, and the maximum vibration mode according to its inherent frequency appeared at the edge of the structure, some vibration modes were orthogonal, the main vibration modes appeared in the forms of bending, torsion, but the stretching vibration mode was scarce. The low orders inherent frequency greatly effected more than the high orders inherent frequency by harmonic response analysis, and the maximum deformation value was 25μm in low order vibrations. The conclusion is that the reinforcing rib structure fulfills design requirements and operates softly.