Micro wave atomic clocks based on trapped ions have advantages in miniaturization and mobility.Therefore,they have attracted widespread attention.Among them,the 113 Cd+ion has become the main candidate ions for the new generation of practical ion microwave clocks due to its advantages of low laser requirements and large ground-state hyperfine splitting frequency.In recent decades,multiple experimental teams at home and abroad have conducted research on cadmium-ion microwave clocks.This article provides a detailed introduction in chronological order of the technical routes and the latest developments adopted by different experimental teams at home and abroad in the research of cadmium-ion microwave clocks.