Abstract: On the basis of the radar theory, combined with the engineering example, this paper expounds the application of GPR in the detection of foundation pit excavation in the disease. Through the analysis of the mechanism of foundation diseases, summarizes the typical characteristics of the soil foundation diseases such as osteoporosis, image separation and slippage line profile measured in the radar chart and the single waveform, and determine the extent of disease and the spatial position of the foundation, the project also uses the site excavation and penetration test of ground penetrating radar detection results; practice has proved that the ground penetrating radar technology is an effective method for rapid detection of foundation diseases, it is worth to popularize.