The utility model provides a sand mould bottom plate, including bottom plate bottom (1) and bottom plate upper portion (2), its characterized in that, bottom plate upper portion (2) middle part sets up the spill and pours groove (3), wherein, it is outside arc to pour the long limit in groove (3) both sides. Through the utility model provides a sand mould bottom plate has enlarged and has welded muscle bottom area to guarantee welded joint flange of rail intensity. Enlarge and weld the muscle area, be favorable to reducing the casting and press from both sides the sediment probability, improve the joint performance.