The conventional Ni-Y0.16Zr0.84O1.92 anode in solid oxide fuel cells fueled with hydrocarbon fuels is prone to suffer from carbon deposition. In this work, we employed an in-situ solvothermal method to decorate the Ni-Y0.16Zr0.84O1.92 anode with Gd0.1Ce0.9O1.95-δ nanoparticles to improve its resistance to carbon deposition and thus improve the electrochemical performance of the cell. This method generates small Gd0.1Ce0.9O1.95-δ particles and at the same time does not block the gas diffusion channels. The Gd0.1Ce0.9O1.95-δ-decorated anode showed enhanced long-term stability in methane with no significant performance degradation after 700 at 750 °C, whereas an untreated Ni-Y0.16Zr0.84O1.92 anode only worked for less than 8 h under the same conditions. The addition of Gd0.1Ce0.9O1.95-δ nanoparticles was found to enhance internal reforming reactions of methane by the distribution of relaxation times technique. This work demonstrated that in-situ solvothermal modification strategy can provide anodes with excellent carbon deposition resistance.