The experimental modal analysis (EMA) applied in vibrating solidification and vibrating ageing of the cast iron elements has been discussed in this paper. The stimulating frequency、excitation area(wave crest)、supporting area and the way of excitation of this cast iron element can be chosen accurately according to the eigenvalue of vibration parameters and the dynamic display of the measurement. If multiple excitation is needed，the principle natural frequency can be adjusted according to the dynamic display as the partial differences and the characteristics change of the elements. The experiment shown that using EMA excitation parameters can get a better technical effect than those of static solidification、heat ageing or other experience excitation ageing. Vibrating solidification can make a fine crystalline and the hardness of the full section is relative high; Vibrating ageing can get a better stress distribution and raise the ability of anti-deformation.