Hydrogeological drilling same-diameter twice-pumping test device

The invention discloses a hydrogeological drilling same-diameter twice-pumping test device which comprises a drilling well and a pumping test device arranged in the drilling well. The drilling well isdivided into an upper water layer located below a surface layer, a water-resisting layer and a lower water layer. The pumping test device includes a large-diameter well pipe and a small-diameter wellpipe. The outer wall of the large-diameter well pipe is sequentially filled with a lower gravel layer, a water-stopping clay layer, an upper gravel layer and a cement well cementation layer from bottom to top, the side wall of the large-diameter well pipe is provided with upper layer water-permeable hole corresponding to the position of the upper water layer and a lower layer water-permeable holecorresponding to the position of the lower water layer, a water-stopping tray is disposed at the position in the large-diameter well pipe corresponding to the water-stopping clay layer, the middle ofthe water-stopping tray is