Composite materials have been widely used across industry sectors. However, they are characterized by a variability of thermal conductivity with the architecture and manufacturing processes. Hence, thermal transfer in composite materials requires an improved fundamental understanding. From numerical purposes, the Finite Element Method (FEM) seems a robust method to study heat transfer in composite material. However, it does not establish a high-fidelity with the real life of material since it is difficult to take into account potential damage matrix or interface imperfection by this method. As such, this paper discusses the development of numerical approach based on the Discrete Element Method (DEM) to study heat transfer in composite materials. For that purpose, we consider a hybrid lattice model based on the equivalence between a particulate domain and a continuous medium. Several works have used the DEM to study heat transfer in a homogeneous and continuous medium. Through this contribution, we aim to extend this approach to investigate composite materials. The model is then validated in terms of temperature by comparison with numerical and experimental results through several applications. Furthermore, a special care taken in the evaluation of the heat flux density fields. To the knowledge of the authors, previous works did not interest to the examination of heat flux density when using the DEM. Indeed, this sensitive to the packing configuration and consequently always heterogeneous even if there typically homogeneous. To overcome this problem, an original smoothing technique called Halo is proposed and discussed in this work. Results exhibit the relevance of the proposed approach to evaluate both temperature and heat flux density fields with a good degree of precision compared with th FEM, the Fast Fourier Transformer (FFT) based method and experimental data.