Abstract: To meet the demand for data collection and feature extraction of radar echo characteristics near the soil surface covered with vegetation, the Monte Carlo method and digital elevation model were used to simulate the layered surface composed of air, vegetation, and soil. The Ulaby double-scattering model was used to simulate the dielectric constant of vegetation, and the modified DeLoor model was used to calculate the dielectric constant of oil-polluted soil. The finite-difference time-domain method was used to study the composite electromagnetic scattering characteristics of the layered surface and buried oil pipeline. The effects of electromagnetic wave incidence angle, vegetation water content, vegetation height, soil water content, degree of oil pollution in soil, terrain conditions, burial depth of pipelines, and pipeline materials on the composite scattering coefficient were analyzed. The results show that the composite scattering coefficient oscillates with the scattering angle and produces a scattering enhancement effect in the specular reflection direction. The composite scattering coefficient increases with the increase of incidence angle and vegetation water content, decreases with the increase of oil content in soil, burial depth of pipelines, and dielectric constant, and varies complexly with vegetation height, terrain, and soil water content, with no fixed pattern. This study provides important theoretical and practical guidance for understanding the electromagnetic scattering behavior of buried targets under complex layered surfaces, optimizing electromagnetic wave detection systems, and particularly for the detection and identification of buried targets under different surface conditions.