The invention discloses a memory device and a forming method thereof. The forming method for the memory device is characterized by comprising the following steps: offering a substrate having a memory cell on the surface; the memory cell comprises a first dielectric layer, a floating gate layer, a second dielectric layer, a control gate layer and a first mask layer; a second mask layer is formed on the surface of the side wall of the memory cell, the second mask layer covers the side walls of the first mask layer, the floating gate layer and the second dielectric layer and partial side wall of the control gate layer being close to the floating gate layer; the first mask layer and the second mask layer are used as the mask, partial control gate layer is removed, thus the size of exposed control gate layer being parallel to the surface direction of the substrate is reduced; after removing partial control gate layer, the first mask layer and the second mask layer are also used as the mask, and the self-aligning silicification process is adopted for forming electric contact layers on the surface of the side wall of exposed control gate layer and on the surface of the exposed substrate. The performance of the formed memory device is improved.