Abstract: As cement contents increase,the stronger the strength of cement-loess becomes. Wherever,incremental extent of strength of cement-loess with cement contents increment becomes bigger when cement contents are little and vice versa.Latter-day strength of cement-loess is worthy of being expected when cement contents are big or dropping energy is big.The effect of side-stress to improve cement-loess axial compressive strength is little.The effect of cement content to the optimization water-ratio and the biggest dry-density of cement-loess is also little.Water-stability of cement-loess(especially cement contents are big) is good.There are many new crystal-substances which are created in the cement-loess.The factors to affect cement-loess strength include ingredients of every crystal-substance content.From the constitutive relation of cement-loess,cement-loess has a critical cement content(about 12%).When cement contents are higher than the critical cement content,cement-loess becomes a brittle material through destruction-strain and distortion-module of cement-loess.