Recently, the monograph Precision Measurement of Time Frequency Signal compiled by Li Xiaohui, Yang Xuhai, et al., researchers of the National Time Service Center under the Chinese Academy of Sciences, was published by Science Press. Giving a systematic introduction to the basic theory, technologies and methods, current research situation and development trend of time frequency signal measurement, the monograph can be regarded as the important reference for measurement and study on time frequency signal as well as learning of postgraduates of relevant majors.