Abstract: In this paper problems of dynamic stability of memberswith elastic support had been investigated. The critical frequency andunsteadiness border of bars were derived. The effects of spring stiffnessand damping on dynamic stability of bars were studied. Research make knowthe side direction stiffness of members more greatly dynamic stability ofstructure more better, the advantageous effect is taked in the vibration tomembers of damping. Some suggestions were given for reducing the vibrationof bars in practical engineering fields.