On the basis of the conventional Halbach array permanent magnet motor. A coreless direct drive permanent magnet wind generator with module poles and Halbach arrays was proposed. The structure and advantages of this kind of motor were introduced . With the help of two dimensional (2D) finite element analysis (FEA), we find out the correct combination way of realizing the unilateral magnetic shielding capability and the size of soft magnetic material of rotor poles was optimized, the pole arc coefficients of motor were determined. Compared to traditional permanent magnet motor with Halbach arrays, the optimized novel machine improved the waveform sine degree, reduced the cost and has less permanent magnets based on ensuring a certain extent of air gap magnetic density.