A position measuring mechanism comprising: a base; a moving portion capable of moving relative to the base; at least one magnet array disposed in the moving portion; a first sensing portion and a second sensing portion respectively disposed on the base at intervals for sensing a magnetic field of the magnet array; a third sensing portion having a signal unit disposed on the moving portion, and a sensitive element disposed on the base for sensing the signal unit; and a processing portion receiving sensing signals of the first sensing portion and the second sensing portion respectively, calculating a subcycle( α 1, α 2, 414, 422) corresponding to the magnet array, and performing operation in conjunction with sensing data of the sensitive element to obtain a movement path of the moving portion, and then feeding the movement path back to a driver to adjust a movement pattern of the moving portion; wherein the magnet array has a plurality of magnets, a minimum distance between the two magnets of a same magnetism is a magnetic period (τ) of the magnet array, and a length of the magnet array is an integral multiple of the magnetic period (τ) of the magnet array, wherein the driver controls a current of a stator provided on the base, and uses a fieldbus to connect to a motion controller, wherein the first sensing portion and the second sensing portion respectively include eight magnetic sensitive elements (H1,H2,H3,H4,H5,H6,H7,H8), and each of the magnetic sensitive elements (H1,H2,H3,H4,H5,H6,H7,H8) is arranged in order from left to right at a distance of a quarter of the magnetic period (τ) of the magnet array, the first magnetic sensitive element is connected in parallel with the fifth magnetic sensitive element, the second magnetic sensitive element is connected in parallel with the sixth magnetic sensitive element, the third magnetic sensitive element is connected in parallel with the seventh magnetic sensitive element, and the fourth magnetic sensitive element is connected in parallel with the eighth magnetic sensitive element; wherein the first sensing portion is located on a left side of the stator, and the second sensing portion is located on a right side of the stator; a separation distance between the first sensing portion and the second sensing portion is an integral multiple of the magnetic period (τ) of the magnet array; a length of the magnet array is greater than the separation distance between the first sensing portion and the second sensing portion, and is at least four magnetic periods (τ) of the magnet array; and the third sensing portion provides a juncture as a reference to combine signals of the first sensing portion and the second sensing portion. a base; a moving portion capable of moving relative to the base; at least one magnet array disposed in the moving portion; a first sensing portion and a second sensing portion respectively disposed on the base at intervals for sensing a magnetic field of the magnet array; a third sensing portion having a signal unit disposed on the moving portion, and a sensitive element disposed on the base for sensing the signal unit; and a processing portion receiving sensing signals of the first sensing portion and the second sensing portion respectively, calculating a subcycle( α 1, α 2, 414, 422) corresponding to the magnet array, and performing operation in conjunction with sensing data of the sensitive element to obtain a movement path of the moving portion, and then feeding the movement path back to a driver to adjust a movement pattern of the moving portion; wherein the magnet array has a plurality of magnets, a minimum distance between the two magnets of a same magnetism is a magnetic period (τ) of the magnet array, and a length of the magnet array is an integral multiple of the magnetic period (τ) of the magnet array, wherein the driver controls a current of a stator provided on the base, and uses a fieldbus to connect to a motion controller, wherein the first sensing portion and the second sensing portion respectively include eight magnetic sensitive elements (H1,H2,H3,H4,H5,H6,H7,H8), and each of the magnetic sensitive elements (H1,H2,H3,H4,H5,H6,H7,H8) is arranged in order from left to right at a distance of a quarter of the magnetic period (τ) of the magnet array, the first magnetic sensitive element is connected in parallel with the fifth magnetic sensitive element, the second magnetic sensitive element is connected in parallel with the sixth magnetic sensitive element, the third magnetic sensitive element is connected in parallel with the seventh magnetic sensitive element, and the fourth magnetic sensitive element is connected in parallel with the eighth magnetic sensitive element; wherein the first sensing portion is located on a left side of the stator, and the second sensing portion is located on a right side of the stator; a separation distance between the first sensing portion and the second sensing portion is an integral multiple of the magnetic period (τ) of the magnet array; a length of the magnet array is greater than the separation distance between the first sensing portion and the second sensing portion, and is at least four magnetic periods (τ) of the magnet array; and the third sensing portion provides a juncture as a reference to combine signals of the first sensing portion and the second sensing portion.