Abstract: The 5A06 aluminum alloy is one kind of basic welding materials, but its thermo phy sical parameters, especially at the high temperature, have been hardly determined under the general project condition, which have great influence on the accuracy of engineering computation.The best annealing temperature of 5A06 Al alloy was confirmed with engineering experiment, based on the rebound after annealing, and the finite element model was built, and the thermo physical parameters were estimated with the probability design system (PDS)in the finite element software ANSYS.The analysis indicated that, the obtained material attribute values accord with the project reality.The use of the probability design system provides one of the phenomenological effective methods for the solution of the unknown material attributes.