Higher frequency ground-penetrating radar (GPR) is becoming more common for various applications. It can achieve higher resolution, but, at the same time, it becomes sensitive to heterogeneous soil, resulting in unwanted scattering appeared in data, which makes analysis and interpretation of the data difficult. In this paper, a simple model is proposed as a tool to evaluate the influence of heterogeneity of soil on scattering. The modeling demonstrates the scattering caused by soil heterogeneity is characterized as the Mie scattering. The influence of soil heterogeneity on GPR measurements is investigated through the modeling. The results exhibit that the amount of permittivity variation of soil is mostly dominates the scattering power; however, when correlation length of soil permittivity distribution is at multiples of wavelength, the influence of correlation length becomes greater.