Abstract: With the development of intelligent transportation, the demand for high accuracy time and frequency is gradually increasing. At present, high-performance atomic frequency standard is widely used in the measurement industry, and the demand for remote calibration of atomic frequency standard is also increasing. Taking NIMDO as the reference time and frequency source, the NTP and rubidium atomic frequency standards are calibrated by remote calibration, which solves the problem of time traceability in the traffic field, provides a legal basis for measurement results and greatly improves the calibration efficiency.