The mobile time-frequency system has the characteristics of highly integrated equipment, convenient and flexible transfer, but the vibration of the mobile platform, the temperature and humidity conditions in the shelter and the stability of the power supply and other factors can lead to the increase of the noise of the atomic clock, thus reducing the accuracy and stability of the time and frequency signals. According to the characteristics of the mobile time-frequency system, this article focuses on the time keeping strategy of the mobile time-frequency system, including the type and quantity configuration analysis of the mobile atomic clock, the recovery and monitoring methods of the time-frequency signal after the mobile. The research results can be used as reference for the development of the mobile time-frequency system.