The invention discloses a rail-bound vehicle aramid-fiber honeycomb side ceiling and a preparation method therefor. The aramid-fiber honeycomb side ceiling comprises an aramid-fiber honeycomb core, an upper panel laminated to the upper surface of the aramid-fiber honeycomb core and a lower panel laminated to the lower surface of the aramid-fiber honeycomb core, wherein each of the upper and lower panels comprises a flame-retardant epoxy resin composite fiber fabric layer and a flame-retardant epoxy resin composite chopped fiber mat layer, the chopped fiber mat layer in the upper panel is laminated to the upper surface of the aramid-fiber honeycomb core, the chopped fiber mat layer in the lower panel is laminated to the lower surface of the aramid-fiber honeycomb core, a U-shaped connecting member which is used for being connected with a crossbeam of a rail-bound vehicle is mounted at the upper end of the rail-bound vehicle aramid-fiber honeycomb side ceiling, and lock-hole inserted parts are embedded at the lower part of the rail-bound vehicle aramid-fiber honeycomb side ceiling. The rail-bound vehicle aramid-fiber honeycomb side ceiling is light in weight and high in strength and can reach the flame-retardant standard; and the preparation method for the rail-bound vehicle aramid-fiber honeycomb side ceiling is low in production cost and is applicable to the small-scale development of rail-bound vehicle side ceilings.