Abstract: This paper expressed the basic principles of Ground Penetrating Radar (GPR) detection method, as well as the choices of radar antenna center frequency in the detection. In addition, the typical highway diseases were also discussed, such as the lessdense roadbed or void, the subsidence of bridge strap and the foundation void near the pipe culvert, by exploring why those problems happened and how they were shown on the radar detection profile map. Those work might provide the reliable basis for the highway disease treatment and highway maintenance work. Through investigating those issues, it is demonstrated that the GPR is quite a cost-effective, high efficient and scientific method in the detection of highway disease.