To control the pore size of anode in thin film solid oxide fuel cells, a simple polymer injection method was introduced to replace conventional anode functional layer method in this paper. Firstly, the liquid polystyrene was pressed and injected to the porous nickel oxide yttria-stabilized zirconia (NiO-YSZ) substrate. Then, a 300-nm-thick film was deposited on a composite substrate by sputtering procedure. Finally,by removing polystyrene from the pore of substrate through pyrolysis, a free-standing thin film on the porous substrate could be obtained. The polymer-injected NiO-YSZ substrate has more controlled pores. Moreover,with the proposed method, throughput of large scale thin film solid oxide fuel cell can be improved.