Abstract: As an important hazardous geological phenomena,caves in loess area have caused loss and damages to various constructions.In particular,the loss and damage to highways are the most distinctive.Site investigation proves that caves in loess have led to different damages to road bed,slopes,bridges,tunnels and drainage facilities of highway.Such damage shows certain regularities in the types,positions and degrees.To understand the essential regularities and mechanisms of the damage caused by caves in loess and guide the stability evaluation and prevention of caves of highway in loess,the geological mode and mechanism of damage of caves in loess to road bed,slopes,bridges,tunnels and drainage facilities of highway are summarized on the basis of widespread site investigations on the highways in Shaanxi and Gansu provinces.