A shock absorption and insulation supporting seat with a transverse elastoplasticity beam falling prevention device comprises the beam falling prevention device, an orbit and a bridge supporting seat which comprises an upper supporting seat plate, a middle supporting seat plate and a lower supporting seat plate which are sequentially connected and fixed. The orbit is a troughlike orbit and is connected to and fixed on the lower supporting seat plate along the direction of a bridge. The beam falling prevention device comprises a plurality of cantilever beams having the same strength, one end of the beam falling prevention device is connected to and fixed on the upper supporting seat plate, and the other end is inserted into the orbit. The middle supporting seat plate of the bridge supporting seat is a spherical supporting seat and also comprises a rotating spherical surface and a sliding surface, the rotating spherical surface is connected to and fixed on the spherical surface structure at the upper part of the middle supporting seat plate, and the sliding surface is connected to and fixed on the spherical surface structure at the lower part of the middle supporting seat plate. The beam falling prevention device has elastoplasticity, prevents a beam body from widthwise shedding from the supporting seat, has the capability for absorbing shock and dissipating energy along the transverse direction of the bridge, and has simple structure and convenient field installation.