Development of the Theory Models of Strength in MacroDefectFree Cement Materials Xiang Xin Li BeixingMacrodefectfree cements have become an important orientation of modern advanced cementitious materials. The development of the theory models of the relationship between porosity and strength, fracture mechanics, fibrillar pullout, microstructure and microchemistry in macrodefectfree cement materials is reviewed. The advances of the theory models will supply guidance for the design and manufacture of superhigh strength cement based materials.: cement; polymer; macrodefect free; strength; theory modelXiang Xin: Editor,Journal Editorial Department,WUT,Wuhan 430070,China.