A position sensing mechanism comprising: an encoding element having an absolute column magnetic track and an incremental column magnetic track extending side by side with each other along a virtual moving axis; a reading element adjacent to and spaced apart from the encoding element, and changing in position relative to the encoding element on the moving axis, the reading element having a first magneto-resistive unit acted on by the absolute column magnetic track, and a second magneto-resistive unit acted on by the incremental column magnetic track; and a processing unit electrically connected to the reading element for receiving signals generated by the first magneto-resistive unit and the second magneto-resistive unit under actions of the absolute column magnetic track and the incremental column magnetic track respectively, and analyzing positions with the signals received; the first magneto-resistive unit and the second magneto-resistive unit are tunneling magneto-resistors respectively, each of the first and second magneto-resistive units (31, 32) having a reference layer and a free layer, and each reference layer and free layer having a magnetic moment, respectively, characterized in that magnetic moments of the reference layer and the efree layer of the first magneto-resistive unit and the second magneto-resistive unit, respectively, are perpendicular to each other, and in the reference layer and the free layer, the magnetic moment of one of the layers is parallel to a sensing film surface of the first magneto-resistive unit, and the magnetic moment of the other layer is perpendicular to the sensing film surface; wherein the magnetic moment perpendicular to the sensing film surface is the magnetic moment of the reference layer or the magnetic moment of the free layer; wherein the reading element further comprises a chip, and the first magneto-resistive unit and the second magneto-resistive unit are respectively formed on the chip; wherein the first magneto-resistive unit has a single magnetic tunneling junction; and wherein the second magneto-resistive unit is a bridge tunneling magneto-resistor. an encoding element having an absolute column magnetic track and an incremental column magnetic track extending side by side with each other along a virtual moving axis; a reading element adjacent to and spaced apart from the encoding element, and changing in position relative to the encoding element on the moving axis, the reading element having a first magneto-resistive unit acted on by the absolute column magnetic track, and a second magneto-resistive unit acted on by the incremental column magnetic track; and a processing unit electrically connected to the reading element for receiving signals generated by the first magneto-resistive unit and the second magneto-resistive unit under actions of the absolute column magnetic track and the incremental column magnetic track respectively, and analyzing positions with the signals received; the first magneto-resistive unit and the second magneto-resistive unit are tunneling magneto-resistors respectively, each of the first and second magneto-resistive units (31, 32) having a reference layer and a free layer, and each reference layer and free layer having a magnetic moment, respectively, characterized in that magnetic moments of the reference layer and the efree layer of the first magneto-resistive unit and the second magneto-resistive unit, respectively, are perpendicular to each other, and in the reference layer and the free layer, the magnetic moment of one of the layers is parallel to a sensing film surface of the first magneto-resistive unit, and the magnetic moment of the other layer is perpendicular to the sensing film surface; wherein the magnetic moment perpendicular to the sensing film surface is the magnetic moment of the reference layer or the magnetic moment of the free layer; wherein the reading element further comprises a chip, and the first magneto-resistive unit and the second magneto-resistive unit are respectively formed on the chip; wherein the first magneto-resistive unit has a single magnetic tunneling junction; and wherein the second magneto-resistive unit is a bridge tunneling magneto-resistor.