Based on the introduction of the principle of ground penetrating radar (GPR) and the processing of contaminated data with strong background noise, this paper shows some case studies of GPR with low frequency antennas applied in identification of lithologic boundary and weak geological body, detection of active fault and fissure, and delineation of riprap interface. These cases show that in order to obtain GPR data with high resolution, it is important in information collection, field reconnaissance, interference factor analysis, data acquisition, and comparison of data processing flows. The discussion in this paper is helpful to the deeper exploration by GPR with low frequency antennas.