Abstract: In order to better interpret the echo data of ground-penetrating radar (GPR), a two-dimensional finite difference time domain model is established to simulate the GPR detection of underground layered structure (concrete/clay layer) and multiple buried targets (metal plate or strip, hole, water or oil pipe). For the model, the interface in the underground layered structure is set to a rough interface, and the electromagnetic differential Gauss pulse is used as the GPR source. To simulate the unbounded scattered field existing in an infinite free space, the computing region is truncated by using the uniaxial perfectly matched layer medium. The simulation results of GPR B-scan echo are obtained by numerical calculation, the effects of target depth, geometry shape, permittivity and conductivity on the scattering characteristics are discussed, and the change of target echo shape produced by the influence of rough surface with different roughness on the target is analyzed. The results show that the shape, orientation, amplitude strength and arrival time of each echo are consistent with the shape, location, medium characteristics and buried depth of each structure in the model, which verifies the validity of the calculation model.