Abstract: Commercial CFD code CFX 12.0 was used as an approach to investigate the flow and convective heat transfer phenomena of a typical 7-pin fuel bundle with wrapped wire. The pressure drop coefficient and Nusselt number under different Re were obtained, and the simulation results are in good agreement with empirical correlations. The transverse flow effects in three kinds of typical subchannels were investigated, and its features were analyzed. The results show that the corner channel’s transverse flow intensity varies heavily along the axial direction, and the transverse flow intensities in three typical subchannels show periodic feature. The local Nusselt number distribution on three cross sections of the central rod surface was also analyzed. The results show that the minimum local Nusselt number occurs close to the contact location of wire and rod, which means that the convective heat transfer condition is the worst in such area, and the special attention in accident analysis is deserved.