According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain. According to the time & space conversion relations and different frequency phase detection principle, an ultra-high precision time & frequency measurement method is proposed in this paper. Higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length. The measurement precision better than 10 picoseconds can be easily obtained. The method develops the length vernier utilizing the stability of signal’s transmission delay, minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal, approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides, the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency. Experimental results show the method can improve the measurement precision to 10 12 / s in the time & frequency domain.