Abstract: Spray forming (SF) is a novel rapid solidification technique. Compared with traditional cast & wrought and powder metallurgy technique, it has the advantages of less segregation and shorter process. In this work, a new third generation powder metallurgy (PM) superalloy FGH100L was prepared by SF hot isostatic pressing (HIP) isothermal forging (IF) heat treatment (HT) process. The effects of solution heat treatment temperatures and preparation process on the microstructure and mechanical properties of FGH100L alloy were studied. The results show that the microstructure of SF HIP IF state FGH100L alloy is very sensitive to changes of solution temperature. With the increase of the solution temperature (1110 similar to 1170 degrees C), the grain size of the alloy grew, and the size of the gamma' strengthened phase first increased and then decreased. Its hardness, tensile strength and plasticity at room temperature/high temperature all show a trend of increasing followed by decreasing. The quantitative equilibrium of three sizes of gamma' phase in the alloy is more reasonable, the microstructure of the alloy is the best, and the hardness and room temperature/high temperature tensile properties of alloy have the highest parameter values at 1130 degrees C. At the same temperature, the grain size of FGH100L alloy increased first and then decreased under different processing conditions of SF, SF HIP HT and SF HIP IF HT. The morphology of grains changed from subspherical to polygonal to subspherical. Alloy grain size increases, and the grain boundary bending degree decreases in the process of SF HIP HT. Due to SF HIP IF HT process, the alloy recrystallizes, refines the grain, and presents chain-like structure, forming curved grain boundary and having higher yield strength. Under SF HIP HT and SF HIP IF HT processes, the tensile fracture of the alloy at room temperature changed from intergranular brittle fracture to transgranular and intergranular mixed fracture, and the tensile fracture at high temperature was intergranular fracture.