In several locations of the pressurized water reactors, dissimilar metal welds using inconel welding wires are used to join the low alloy steel components to stainless steel pipes. To evaluate the integrity and design the dissimilar welds, tensile and fracture property variations are needed. In this study, dissimilar metal welds composed of SA508 Gr.3, inconel 82/182 weld, and TP316 stainless steel were prepared by gas tungsten are welding and shield metal arc welding technique. Different tensile properties were observed depending on the specimen sampling position at room temperature and 320 °C using round bar and mini-sized tensile specimen. In addition, fracture toughness were also observed at the bottom, middle, and top of the welds at the same temperature condition. Using small punch (SP) test method, correlations between mechanical property and SP data for estimating tensile and fracture toughness were carried out. Also, SP test was simulated by Abaqus program, finally from the FEM model of small punch test, detailed fracture toughness could be calculated and compared with CT specimen test results.