A non-volatile memory device includes a substrate. A plurality of shallow trench isolation (STI) lines are disposed on the substrate and extend along a first direction. A memory gate structure is disposed on the substrate between adjacent two of the plurality of STI lines. A trench line is disposed in the substrate and extends along a second direction intersecting the first direction, wherein the trench line also crosses top portions of the plurality of STI lines. A conductive line is disposed in the trench line and used as a selection line to be coupled to the memory gate structure.