Abstract: The mechanical properties of 316L brazed joints were studied by using high temperature tensile test and mathematical model analysis. To get a good understanding of the failure mechanism of brazed structure, the microstructures of crack tip and brazed seamwere studied. The results indicate that the load-displacement curves match the process of crack initializing and propagating clearly. And the suitable testing rate range is 1mm/min~2mm/min. Furthermore, the concentration phenomenon of Fe is the main cause of the fracture in plate-fin structure.