In the construction sites of Shandong University and Central Stadium for Olympic Games in Jinan, the ground-penetrating radar was adopted to investigate the karst foundation and, as a result, the development situation of karst fissures was ascertained rapidly and effectively. Engineering practice shows that, in the engineering application, geological survey data should be analyzed thoroughly at the early stage to rationally determine the detection parameters, and the investigation should be combined with such methods as engineering drilling so as to continuously accumulate experience and obtain satisfactory engineering results.