Abstract: The mechanism of polymer modified cement based materials was reviewed in recent years at home and abroad, from the angle of theory, the mechanism of polymer modified cement based materials has carried on the induction and summary,the modified mechanism of the polymer modified cement base material was discussed mainly from four aspects, the influence of polymer to cement hydration process include physics and chemistry function;The effect of polymer on the microstructure was made from latex particle dispersion and the formation of polymer film.From the pore structure, polymer changed the pore size distribution, the characteristics of the pore diameter and average pore diameter and most probable aperture, porosity of cement based materials, and so on, and improves the cohesive strength.In terms of the structure of the polymer itself,the chain structure and state of aggregation structure of polymer directly affects the performance of cement based materials.

Key words: polymer;modified cement based material;mechanism;microstructure;pore structure