The grain growth behavior of NiO nano grains in mesoporous gadolinium-doped ceria (GDC) network was investigated for anode materials of intermediate-temperature solid oxide fuel cell (SOFC). Both mesoporous GDC and NiO-GDC powders were synthesized using tri-block copolymer, Pluronic F127 as a structure-directing agent, and then X-ray diffraction, N2 adsorption/desorption isotherms, thermo gravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were used for characterization of the mesoporous structure. Mesoporous GDC synthesized using pluronic F127 triblock copolymer had ordered double mesoporous structure with an average pore size of 9.68 nm and was thermally stable up to 700 degrees C. NiO grains in the mesoporous GDC network grew to have an octahedral shape with truncated-edges, but massive NiO agglomeration occurred as the calcination temperature increases up to 850 degrees C.