In this paper, we reported the fuel cell performance with La0.8Sr0.2MnO3 (LSM)/Ce0.8Sm0.2O1.9 (SDC) composite cathode prepared from LSM powders of different particle sizes via the silk-printing technique. It was found that the change in particle size ofLSM nanoparticle from 40 to 90 nm resulted in an increase in the maximum power density from 132 to 228 mW/cm2 at 650 ℃ with H2 as fuel and O2 as oxidant. And the polarization resistance of the electrode decreased from 2.547 to 1.034 Ω.cm2. Concerning the particle size of electrode materials, a higher activity was anticipated with smaller particles because a large number of TPB or electrode surface sites along with a higher porosity could be developed. However, this study showed that the electrode prepared with particles of larger diameter had fine and uniform microstructure resulting in higher power density and lower overpotential, where homogeneous distribution of particles and pores was beneficial for increasing the electrochemical active area and the electronic conductivity of the electrodes as well as the gas diffusion for the reactants.