A serial of experiments have been conducted to investigate the flame height and air entrainment rate of the ring pool fire. The outside diameters of ring pool fires are 15 cm, 20 cm, 25 cm, 35 cm, 45 cm and 55 cm, respectively. The difference between the inner diameter and the outer diameter is 10 cm for each pool. It was found that the flame height of ethanol changes slightly with the increasing equivalent pool diameter, while the ones of n-heptane increases obviously. A unified correlation considering the air entrainment has been developed for both two fuels, and the measurement collapsed well with the physical model.