Polymer-modified cement-based materials are commonly used in engineering applications and have achieved good results. The interactions between polymer and cement have received extensive attention. In this paper, the interaction between them is discussed and summarized by reviewing the existing technologies. Traditional experimental methods do not provide a comprehensive picture of the interaction between polymers and cement-based materials, molecular dynamics (MD) simulations were used recently in the study of inorganic-organic phase interactions. People almost reach a consensus on the modification mechanism of polymers on concrete at micro-scale. But at nano-scale, the interaction between polymers and cement is an ongoing work, researches show that it contains several aspects, i.e., chemical bonding, hydrogen bonding, van der Waals forces, etc. Different polymers may have different types of interactions with cement. Understanding these interactions is important to elucidate the relationship between the microstructure and macroscopic properties of polymer-modified cement-based materials. Molecular dynamics simulation has proved to be an effective method to study the interactions between inorganic-organic composites at this stage but has some limitations.