The invention discloses a railway truck and a side wall thereof. The side wall comprises sleeper columns and side columns which are arranged in the length direction at intervals; the side wall furthercomprises side plates, and the side plates are fixedly connected between the adjacent side columns as well as between the adjacent side columns and sleeper columns; the side wall further comprises wearing plates used for preventing the sleeper columns, the side columns and the side plates from being directly worn; and curved plates of which the tops and the bottoms are bent inwards and the middles protrude outwards are adopted as the side plates. According to the side wall of the railway truck, the enough transverse stiffness can be achieved without additionally arranging other parts for improving the stiffness, in addition, a bottom plate connected with the bottom of the side wall can be set to have the small width on the precise that the volume of the railway truck is invariable as thebottoms of the side plates are in an inward bent state, and therefore the side wall not only has the enough transverse stiffness, but also can meet the lightweight design requirements of the railway truck.