Abstract: Pd/HZSM-5 coating was prepared on the inner wall of φ3 tubular reactor by gas-aided fluid displacement and electroless plating technologies. The coating was characterized by means of SEM, XRD, and XPS. The coating surface was flat without flaws, with thickness of 12μm~16 μm and catalyst particle of size 1μm~5μm. Metallic Pd particles were uniformly dispersed on the coating surface. The coating was used as the catalyst for the supercritical cracking of n-dodecane, a typical model compound of endothermic fuel. With the temperature of 640℃, pressure of 4MPa, and resident time of 10s, Pd/HZSM5showed very high cracking ratio of 55.5%, hydrogen yield of 3.1%, and heat sink of 3470kJ/kg, which were increased by 8.5%, 58.7%, and 10.5% compared with HZSM-5 coating, respectively. Furthermore, they were 17.3%, 78.1%, and 13.5% higher than the case of thermal cracking reaction, respectively.