In order to obtain an oxide ion concentration profile in solid oxide fuel cell (SOFC) anode, a quenching system of a SOFC single cell has been developed. A SOFC power generation equipment with a nozzle for helium impinging jet, which is covered by a water cooling jacket, was prepared. The quench experiment shows that the temperature of YSZ electrolyte could be decreased from 830 to 150 °C within 1.5 sec, which was in good agreement with analytical results based on the average Nusselt number of impinging jet heat transfer. In addition, a diffusion distance of an oxide ion in YSZ bulk during quenching process was calculated based on the obtained temperature profile with respect to time and a diffusion equation.