Abstract: The pool entrainment is an important phenomenon in LOCA transient in PWR plants, and such a phenomenon may cause further loss of coolant and induce uncovering and melt of fuel. Kataoka & Ishii pool entrainment model is widely used in reactor safety analysis, but is very conservative. The reason is that the model has limited validation against experimental data in high gas flux region and has large uncertainty. An experimental study of air-water pool entrainment with prototypic gas flux conditions of AP1000 was studied. The test section was 2.2 m long and 380 mm in diameter, and built by transparent material for visualization. The range of air flow superficial velocity was 0.98-5.41 m/s. The two-phase mixture level was measured by guided wave radar and the water entrainment was recorded by weight measurement after it was separated from entrainment separator. A correlation of pool entrainment in high gas flux region was proposed based on experimental data obtained in this study. The phenomenon of entrainment saturation was found in high gas flux region.