Abstract: Complex geotechnical conditions of dual zone in limestone area cause frequent landslides, seriously affecting the construction and operation of highway in karst area. With the typical landslide of dual zone in a highway project as example, the study of the mechanism of landslide indicated that the rock-soil mass and the landform are the internal causes, Studying on a high-speed dual-zone geotechnical engineering typical landslide Case. By studying the mechanism that the the cutting excavation is the external cause, the heavy rainfall is the inducement. The mechanism of landslide was summarized as follows:displacement by rainfall (soil in zoneⅠ) and traction (rock in zoneⅡ). Analysis of the landslide stability by using the limit equilibrium method showed that the landslide was basically stable after unloading, but in case of rainfall the landslide remained unstable. Aiming at such particular genesis of the landslide, the integral zoning control scheme based mainly on slide-resistant piles was adopted. The treatment produced good effect, and had advantages of low construction cost and fast construction schedule.