Conjugate heat transfer problems are widespread in practical engineering. Traditional methods such as the Finite Difference Method （FDM） and the Finite Volume Method （FVM） have been widely applied to solve these problems. The Smoothed Particle Hydrodynamics （SPH） method， a meshless particle method， offers advantages such as strong adaptability， suitability for analyzing complex structures， and high flexibility. Therefore， this method has seen extensive application and rapid development in fields such as ship design and geological disaster simulation. However， although there have been some applications of the SPH method in conjugate heat transfer problems， there is currently limited research on simulating heat transfer in actual engineering scenarios involving different functional materials， such as the simulation of heat transfer and heat-generating components. In view of this， we conduct numerical simulations of fluid-solid conjugate heat transfer using the SPH method. First， traditional test cases of natural convection in a closed square cavity and horizontal annular convection are simulated. Then， the focus shifts to simulating natural convection cases involving heat transfer blocks and heat-generating blocks. The results show a high degree of agreement with traditional methods， demonstrating the adaptability and accuracy of the SPH algorithm in simulating conjugate heat transfer problems involving different functional materials. Finally， the simulation of a heat sink with fin structures is carried out， analyzing the impact of parameters such as the heat transfer ratio and heat generation ratio on the cooling performance. These results verify the significant adaptability and flexibility of the SPH method in handling complex cases， providing theoretical support and practical guidance for solving complex engineering problems in the future.