A memory device for sensing memory cell in a memory array includes at least one first memory cell, a first sensing amplifier, a first multiplexer circuit, a plurality of first reference cells, and a controller. The first sensing amplifier is coupled to the at least one first memory cell. An output terminal of the first multiplexer circuit is coupled to the reference terminal of the first sensing amplifier. Each of the first reference cells is coupled to each input node of the first multiplexer circuit. The controller is coupled to a control terminal of the first multiplexer circuit. The first sensing amplifier comprises an output terminal and a reference terminal. The controller controls the first multiplexer circuit to select one of the first reference cells as a selected reference cell to couple to the reference terminal of the first sensing amplifier when each read operation to the at least one first memory cell is performed.