The static spin susceptibility and spectral function of the system corresponding to the magnetic-ion-diluted Kondo insulator is calculated using the framework of dynamical mean-field theory with a coherent potential approximation. The system is described by a periodic Anderson model with randomly distributed impurity sites which have no f electron. The impurity concentration dependence of the static spin susceptibility in the present result is in qualitative agreement with the experimental magnetic susceptibility measurements of (Yb,Lu)B 12 .