Tertiary alkanolamine is a kind of admixture commonly used in cementitious materials. It can significantly change the hydration process of cementitious materials, and affect the strength of cementitious materials. However, the differences of performance and mechanism of tertiary alkanolamine with different molecular structures have not been uniformly explained. In this paper, the influence of tertiary alkanolamine on the strength and hydration of cementitious materials is summarized, and the reasons for the different mechanical properties of cementitious materials caused by tertiary alkanolamine with different molecular structures are explored. Finally, the future research and development trend of tertiary alkanolamine is prospected.