A motor stator includes a bobbin bracket, a modular mounting bracket, and a modular change box. The bobbin bracket includes a plurality of bobbins circularly disposed in a radial pattern. The modular mounting bracket is disposed on the bobbin bracket. The modular mounting bracket is formed with a first slide structure. The first slide structure is perpendicular to an axial direction of the bobbin bracket. A sensing circuit board is disposed in the modular change box. The modular change box is formed with a second slide structure. The second slide structure is perpendicular to the axial direction of the bobbin bracket and slidably connected into the first slide structure, so as to assemble the modular change box to the modular mounting bracket along a radial direction of the bobbin bracket.