Abstract: Based on a generalized variational principle ofmagnetoelasticity for soft ferromagnetic plates, the magnetoelasticstability and post-buckling as well as sensitivity to imperfection areanalytically investigated in the present paper to the ferromagnetic beam-plateswith cantilevered, simply-supported, clamp-supported boundary conditions.The analyses are carried out by means of perturbation technique for theouter and inner fields of ferromagnetic beam-plate and classical Koitertheory. The results achieved show that the stability of cantileveredbeam-plates is sensitive to initial imperfection but is not sensitive toinitial imperfection for simply-supported and clamped beam-plates. Thereasonable explanation is suggested qualitatively for the phenomenon thatthe predicted critical magnetic field of magnetoelastic buckling are alwayslarger than the measured values from experiments.