The multiflash exposure method, which is a new useful and powerful tool for studying the nature of the photolytic silver atom on silver halide grain surface, is reported. The lifetime of the photolytic silver atom and the corresponding activation energy are easily and quantitatively determined by this method. The lifetime at 20 °C and the apparent activation energy were 1.1 s and 0.7 eV, respectively, on (100) surface of a chemically unsensitized silver bromide grain in a wet air environment. In a vacuum environment the lifetime was prolonged to 300 s and the activation energy was decreased to 0.40 eV.