Ni-Fe-Cr alloys have been widely used for petrochemical, chemical and nuclear applica- tion due to their superior corrosion resistance and good workability. Nowadays, Ni-Fe-Cr alloys with high- er strength are demanded for the engineering application. Increasing the carbon content could enhance the strength of Ni-Fe-Cr alloys due to the solid-solution strengthening effect of interstitial carbon atoms. However, an increase in the carbon content would promote the precipitation of carbides, which would re- duce the corrosion resistance. In order to optimize the carbon content and determine the solution treat- ment, microstructure evolution during solution treatment and its effects on the properties of Ni-Fe-Cr al- loys with different carbon content were investigated using OM and SEM. The results show that variation in carbon content affects the carbide dissolution and grain size during solution treatment, which affects the mechanical properties and intergranular corrosion susceptibility of Ni-Fe-Cr alloys. For the Ni-Fe-Cr alloy with carbon content of 0.010%, M23C6 carbides produced during the hot-working process do not ex- ist after solution treatment at 950 ℃. For the alloy with carbon content of 0.026%, M2℃8 carbides are dis-solved into the matrix when the solution temperature increases to 1000 ℃. An increase in the carbon con- tent from 0.010% to 0.026% results in an increased tensile strength and has slightly observable effect on the elongation. The alloys with the carbon content in the range of 0.010%-0.026% have lower intergranu- lar corrosion susceptibility. As the carbon content increases to 0.056%, M23C6 carbides could not be dis- solved even at the solution temperature of 1050 ℃, and inhomogenous grain-size distribution is ob- served. The presence of undissolved M23C6 carbide weakens the solid-solution strengthening effect of car- bon atoms, and significantly increases the susceptibility to intergranular corrosion.