A pixel array module includes a substrate, a pixel electrode array, a patterned conductive layer and a semiconductor circuit unit. The substrate has a first surface and a second surface opposite to the first surface. The pixel electrode array is disposed on the first surface of the substrate. The patterned conductive layer is disposed on the second surface of the substrate, and the patterned conductive layer is electrically connected to the pixel electrode array. The semiconductor circuit unit has at least one input terminal and at least one output terminal, which is electrically connected to the patterned conductive layer. A flat display apparatus is also disclosed.