Abstract: The experimental platform of Tang Qilin as a model was taken. The numerical simulation was implemented on two phase flow and boiling heat transfer characteristics of the tube-bundle vertical channel based on CFX software. The thermal-hydraulic characteristics in the tube-bundle vertical channel can be reasonably captured at different inlet temperatures, heat fluxes and mass velocities. The maximum relative error of average temperature along the height of the tube is 3.5% between numerical simulation and the experiment. The good agreement between them proves that the numerical calculation is correct and exact. On the base, the distributions of velocity could be also obtained, and the effect factors of boiling pressure drop and void fraction were analyzed.