The invention discloses a pump cover of a large scale excavating pump, comprising an irregularly shaped pump cover with the outer edge approximate to a parabola, wherein the outside of the pump cover is provided with reinforcing ribs which are determined through adopting a computer to carry out stress analysis and bearing strain simulation design; moreover, the reinforcing ribs gradually change according to the stress distribution formed by the pump cover and are continuously distributed in a circle; the wall thickness of the reinforcing ribs is gradually thickened in the shape of a ladder along the unfolding direction of an outer edge parabola. The pump cover solves the problem of flat plate bearing through adopting a computer to carry out stress analysis and bearing strain simulation design and consuming least material, thereby preventing the deformation of the pump cover caused by excessive pressure during use and meeting the use function of the pump; both pressure test and on-site operation test confirms the reasonableness of the design which can prevent the deformation of the pump cover exceeding the design data. In addition, the pump cover reduces material consumption and the weight of the pump cover.