Abstract: The present invention provides a side wall of railway wagon and a boxcar of railway wagon. The side wall of the railway wagon comprises an upper side plate, a lower side plate, an inner side stake and an outer side stake, wherein the said inner side stake is arranged at the inner side of the said upper side plate and the said lower side plate, and the said outer side stake is arranged at the upper part of the said side wall of railway wagon and is arranged at the outer side of the said upper side plate. By applying the side wall in the form of internal stakes, the side wall of railway wagon and the boxcar of railway wagon of the present invention can make full use of the width space between the outer surface of the side plate and the outer surface of the side stake on the basis that the external dimension of the railway wagon is not changed, thereby effectively improving the volume of the railway wagon and the transporting capability of the train.