Effect of melt treatment on the microstructure and mechanical properties of a modified inconel 718C alloy was studied in this paper. The results show that, microstructure of finer dendrite, lower segregation and less amount of Laves phase is obtained after melt treatment. Also, smaller γ＇＇ phases with more uniform distribution are precipitating in the specimen via melt treatment. Melt treatment shows no obvious effect on the 25℃ and 700℃ tensile strength, while it evidently improves the tensile plasticity and the stress-rupture property. Specimens via melt treatment at 1 600 ℃ for 10 minutes exhibit best mechanical properties. Extended melt treatment after 10 minutes degrades the mechanical properties.