Grain tank for combine harvester

The utility model relates to a grain tank for a combine harvester. The grain tank comprises a front side wall, a rear side wall and a grain tank base plate which is formed between the front side wall and the rear side wall. The grain tank base plate of the grain tank comprises an arc-shaped bottom and horizontal bottom faces arranged on one side or the two sides of the arc-shaped bottom. The grain tank base plate is arranged to be in the mode combined by the arc-shaped bottom and the horizontal bottom faces, the grain tank can be arranged on a grain tank base in a sitting mode more quickly and precisely in the process that the grain tank is placed on the grain tank base, hence, the production efficiency of the combine harvester is greatly improved, and the manufacturing cost of the combine harvester is lowered.