Abstract: The thermal-hydraulic behavior of triangular arranged fuel bundle with wrapped wire spacer of fuel assembly for sodium-cooled fast reactor was investigated by employing CFD code CFX, and the results were compared with subchannel analysis code SuperEnergy. Fuel bundles composed of 7, 19, 37 and 61 fuel rods were analyzed separately. The axial velocity, cross flow mixing effect, and temperature rise along axial direction for different subchannels of the fuel bundle were discussed, and the effect of wrapped wire spacer was carefully investigated. The results show that the wrapped wire spacer plays an important role on the cross flow effect and axial velocity distribution as well as the temperature rise in different subchannels. Moreover, with the increase of fuel rods, the flow in fuel bundle becomes more complicated, and the non-uniformity of the axial flow also shows a tendency to enhance.