Abstract: In this study, regression analysis on Al₂O₃/H₂Onanofluid properties was made. The growth and departure of the bubble behavior in the Al₂O₃/H₂Onanofluid and pure water flow boiling process were numerically simulated based on Moving Particle Semi-implicit（MPS） method in different conditions. And the comparative analysis was made between the results of pure water and Al₂O₃/H₂Onanofluid under the same conditions. The results indicate that the bubble in Al₂O₃/H₂Onanofluid grows faster and the bubble departure frequency of nanofluids is greater than that of pure water, and the heat flux is also improved in the same conditions. It is convinced that nanofluids can enhance the boiling heat transfer. This work also initially reveals the underlying mechanism why nanofluids can enhance the boiling heat transfer from the point of view of bubble dynamic behavior. In order to investigate the nanofluids application in In-Vessel Retention（IVR） strategy after severe accident happened to the nuclear reactor, the bubble dynamic behavior has been researched. The results indicate that the bubbles in nanofluids can depart from the heat surface earlier than that of the pure water, and this makes the new cooling fluid fill the heat surface timely and enhance the IVR capability.