An experimental study has been conducted to elucidate characteristics of transient heat transfer during quenching a vertical hot surface with a falling liquid film. The experiment was done at atmospheric pressure for the following conditions : an initial surface temperature from 200 to 400°C, a subcooling of 20-80 K, average velocity of 0.52-1.24 m/s, the block material is copper and carbon steel. The surface temperature and heat flux are estimated from the measured temperatures in the block during the quench by two-dimensional inverse solution. It follows that as the position of wetting advances downward, the position at which the heat flux becomes a maximum also advances downward. The time at which the position of maximum heat flux begins to move is one of the most important parameters and can be predicted by a proposed correlation. In addition, it is revealed that the maximum heat flux depends on the length to which it occurs from the leading edge.