Integration and low phase noise are the inevitable trend and practical basis for the development of microwave signal sources. The highly coherent soliton frequency combs in microresonators provide an effective technical approach for the generation of new integrated low-phase noise microwave signals. In this paper, the stable generation and coherent beat frequency of soliton mode-locked frequency comb are realized based on a high-quality magnesium fluoride crystal microdisk cavity. Finally, 15.38 GHz microwave signal with the phase noise of -120 dBc/Hz@10 kHz is obtained, which shows the application advantages of miniaturization and low phase noise. It will provide an important technical support for the development of integrated high-performance microwave signal sources in the future.