A novel substructure of millimeter wave equalizer was designed which was based on the analysis of the characteristic of the planar whispering-gallery modes dielectric resonator and the basis equalizing theory when it coupled with the microstrip line. The simulation shows that the quality factor and the coupling can be easily tuned by changing the parameters of the substructure. At last, a novel millimeter wave equalizer was fabricated by cascading this substructure. And it displays good performance.