Nickel-based superalloys have excellent high-temperature properties due to the dispersion of stronger precipitates in matrix. The properties are significantly affected by the morphology and size of these precipitates. Lattice misfit between precipitates and phases plays an important role on the morphology and size of the precipitates, therefore, an appropriate lattice misfit is desired during the manufacturing of nickel-based superalloy turbine components. The aim of this experiment is to investigate the evolution of lattice parameters and lattice misfit, and the stress relaxation behavior during ageing heat treatment of forged nickel-based superalloy, to reveal the interaction between precipitation process and residual evolution during heat treatment of Ni-base alloys.