Abstract: Taking the imported continuous casting and rolling rod raw materials for production of ER5356 aluminum alloy welding wire as the research object, the high temperature strength and plastic change of the continuous casting and rolling rod at different temperatures (250-550 ℃) were studied by high temperature tensile tests, and the fracture morphology was observed. The best thermoplastic temperature range was obtained. The results show that with increasing temperature, the high temperature strength of the continuous casting and rolling rod showed a single exponential decrease trend, the percentage elongation after fracture increased, and the percentage reduction of area changed little, indicating the continuous casting and rolling rod had good high temperature plasticity. With increasing temperature, the grain boundary weakened, and the area of the intergranular fracture area increased; the tensile fracture morphology changed from dimples to dimples and brittle intergranular fracture mixed morphology, and finally completely changed to the brittle intergranular fracture morphology. The best thermoplastic temperature range of ER5356 aluminum alloy continuous casting and rolling rod was 375-525 ℃.