In order to solve the problem of the Raman effect on the generation of optical frequency comb in microcavities under whispering gallery mode, especially at GHz repetition frequencies, which makes it difficult to generate a very smooth optical comb spectrum. Firstly, design and adjust the coupling length between the waveguide and the microring. Then, optimize the coupling angle, adjust the matching mode between the waveguide and the microring, the coupling Q value in the long wavelength is reduced, the threshold of Raman generation is increased, and the Raman effect is suppressd. According to the simulation analysis, compared with the general straight waveguide microring coupling structure, the designed pully waveguide microring has three times increase in the Raman threshold at the short wavelength, and the optical frequency comb power generated at the short wavelength has increased by 20 dB. This provides a certain reference value for the design of whispering gallery mode microcavity structures.