Carbon nanomaterials have received extensive research and attention because of unique structure and excellent performance to be used as reinforcing materials to improve the performance of cementitious materials. However,the enhancement effect is based on the good dispersion of carbon nanomaterials in the cement. The large specific surface area and strong intermolecular forces of carbon nanomaterials make them difficult to be dispersed in the cement matrix,and the dispersion effect is difficult to judge. This paper systematically sorts out the mechanism of common carbon nanomaterials agglomeration in cementitious materials,summarizes the dispersion techniques adopted by scholars in recent years,analyses the mechanism,advantages and disadvantages of various dispersion methods in detail,and lists the characterization methods for the dipersion effect of carbon nanomaterials in cementitious material. In the future,the research should focus on the development of more efficient and suitable dispersion methods for industrialized production,and the means of evaluating the real dispersion state of carbon nanomaterials in the cement matrix,which can facilitate the scale-up of nanocarbon-modified cementitious composites for application in real engineering projects.