Abstract: Compressive test, collapse test and unconfined compressive strength test were conducted to investigate the compressibility, collapsibility and strength property of loess stabilized by cement kiln ash. Mercury intrusion porosimetry test and scanning electron microscope test were also performed to analyze the changes in the pore distribution characteristics, the contact form of soil particles and the structure of compacted samples for the stabilized loess. The results indicate that adding cement kiln ash to loess can make both the compressibility and collapsibility reduce prominently. The compressibility is reduced from moderate to low, and the collapsibility is reduced from moderate to mild and disappears at last. Furthermore, the strength property is enhanced obviously. The microscopic test results show that inter-aggregate pores in the stabilized loss sample disappear and change into inter-aggregate pores with the increasing cement kiln ash, and the total void ratio is also reduced. The connection between particle is enhanced, making the soil structure more stable.