Abstract: Unfavorable geologic body such as loess pitfall,artifical cavity and waste area have wide development and distribution along the highway in the west of Gansu province, Which has heavy influence on construction of highway,safety of operation,scale of engineeing construction and efficiency of investment. The underlying cavity and waste area have the characteristics of diversification of type, strong dormant character, irrgularity of spatial distribution, unpredicta bility of inbreak and breakdown. In order to improve the precision accuracy of explo- ration, the exploration should insist in the principle of dynamic probe at many stages and comprehesive application of many means to detect and decrease the latent harm progressively. The curing measure of waste area and cavity should in accordance with the factors such as their relation with the spatial location of highway,scale and dimension, stability, state filling situation comparison of technology and surrounding, finally determine after comprehensive and economy. The new technology, method and technique should probe and apply actively.