Tungsten (W) fuzz formed on divertor targets under helium plasma irradiation significantly alters the thermal conduction properties of the underlying W substrate. Hence, it is essential to conduct detailed studies on its thermal conductivity. Modeling heat transfer in the media characterized by complex rough morphology and porous structure is a formidable challenge. To address this, a novel computational framework named Lattice Boltzmann Simulation (LBS), leveraging the lattice Boltzmann method (LBM), has been developed to simulate three-dimensional heat conduction within W fuzz and calculate its effective thermal conductivity (ETC). The modeled ETCs of fuzzy layers with different thicknesses by LBS code show a good agreement with the experimental values measured in the NAGDIS-II device. Furthermore, an empirical fitting formula that describes the temperature-dependent ETC of W fuzz can be derived based on the LBS simulations, enabling rapid thermal conductivity calculations. Leveraging this relationship, a 1D heat transfer model has been utilized to investigate the impacts of W fuzz on thermal conduction for divertor targets with fuzzy surfaces. The results reveal that the formation of W fuzz reduces the critical heat flux required for surface melting, thereby exacerbating the risk of material damage under high heat loads.