The invention discloses an in-layer clamping-sealing layered water injection device. The in-layer clamping-sealing layered water injection device comprises an interlayer clamping-sealing packer, waterdistributors are connected to both the upper end and the lower end of the interlayer clamping-sealing packer, and the interlayer clamping-sealing packer is packed in a thin interlayer, so that an upper water injection layer above the thin interlayer is separated from a lower water injection layer below the thin interlayer. The in-layer clamping-sealing layered water injection device further comprises an in-layer clamping-sealing packer, water distributors are connected to both the upper end and the lower end of the in-layer clamping-sealing packer, the in-layer clamping-sealing packer is packed between an upper thin clamping layer and a lower thin clamping layer which are adjacent to each other, so that an upper lower permeable layer above the upper thin clamping layer and a lower permeable layer below the lower thin clamping layer are separated, and a high permeable layer is arranged between the upper thin clamping layer and the lower thin clamping layer which are adjacent to each other. By means of the in-layer clamping-sealing layered water injection device, the high-intensity packers are utilized to conduct mechanical clamping and sealing on perforation sections of large thicklayers and thin interlayers, the separate-injection rate of layered water injection and the flooding effect are improved, and the device is significant in guaranteeing oil-field high-water-cut periodremaining oil potential tapping, increasing the recovery ratio and lowering the water injection cost.