A series of experiments on water droplet impact on the burning peanut oil were performed to explore the effects of droplet size and falling height on flame expansion scale. Flame expansion phenomenon accompanied by smoke and flame hairs was captured and its mechanism was clarified in detail. Both droplet size and falling height have significant effects on the maximum flame expansion scale. Droplet size determines the flame expansion scale by influencing the mixed amount of water vapor and combustible fuel gas, while the falling height affects the flame expansion scale by suppressing oil droplet splash. Furthermore, the effect of falling height on the flame expansion scale is only significant at smaller droplets. With the increase of water droplet diameter (2.0-4.5 mm) and falling height (45-95 cm), the maximum height of flame expansion is increased to 6-15 times, and correspondingly the maximum volume has an increase of 66742-484073 times.