Disclosed is a magnetic field modeling method of an annular Halbach permanent magnet array. The method comprises the steps that firstly, a global coordinate system is established in space for the annular Halbach permanent magnet array, wherein the center of the annular Halbach permanent magnet array is selected as the original point of the coordinate system; secondly, a local coordinate system isestablished for each magnet of the annular Halbach permanent magnet array, wherein the center of each magnet is selected as the original point of the corresponding local coordinate system; thirdly, atransformation relationship between the global coordinate system and the local coordinate systems is calculated, and the corresponding relationship between the global coordinates and local coordinatesof any position in the space is calculated; fourthly, under each local coordinate system, a surface magnetic charge method or an equivalent current method is utilized to solve the magnetic field intensity generated by the corresponding magnet; finally, the magnetic field intensities generated by all the magnets in the space are superimposed to obtain the magnetic field intensity generated by theannular Halbach permanent magnet array in the space. The method can solve the magnetic field intensity of any position in the space, have the advantages of being small in calculation amount and shortin calculation time and greatly improve the calculation precision and the calculation efficiency.