Abstract: The paper presents a multiple layers backscatter model of wheat for S-band based on vector radiative transfer (VRT) theory, which focuses on the microwave character of wheat at the growth stage that wheat ears appeared. The scattered, absorbed and transferred electromagnetic intensity is analyzed based on the law of energy conservation of VRT, and the wheat canopy is divided into three layers, the ears layer, the stem and leaf layer and the soil layer. Furthermore, the total backscatter is composed by using five back-scattering contributions. An advanced integral equation model (AIEM) is applied to simulate the soil backscatter. The extinction and phase matrices are used to compute the scattering intensity decayed and transferred. In addition, Mueller matrix is used to obtain the backscatter values. The backscatter of S-band, which was measured at the West Sichuan Experiment Location in 2011, is applied to analyze and verify the model. The results show the simulated values agreed well with the measured data, and the wheat ears should be taken into account in modeling as a separate element for its influence to backscatter.