Ground-penetrating radar (GPR) technique was used at University of Technology-Baghdad, as a non destructive, quick, low cost and powerful technique in detecting any change in the constituents of subsurface as materials which can be consequently applied in urban and constructed areas. The main objectives of this study are: to simulate GPR data obtained by 250 and 500 MHz antennas for shallow engineering investigation by detecting different subsurface bodies. A simulation is made for GPR data with different geometric buried bodies and located at different depth. Before processing, most of the raw data of radargram do not reflect the presence of the buried bodies. But after processing by using suitable filters and other interpretation tool parameters, many of the investigated subsurface bodies and structures appeared clearly. It is found from this study that the degree of clarity of the buried bodies do not depend on the higher value of dielectric constant of the body, but it depends on the contrast between the body and the host medium. Thus the body with low dielectric constant appears more clear than that with higher dielectric constant, when they are at the same depth. Most of the buried bodies appeared on GPR radargrams using the medium frequencies. The best detecting depth are 1.5 m to 1 m for 250 and 500 MHz antennas respectively.