Abstract: The sodium-cooled fast reactor is positioned by metal wires, which plays an important role in enhancing coolant mixing, promoting convection heat transfer and reducing mechanical vibration. In this study, the mathematical and physical model of the annular fuel assembly of the sodium-cooled fast reactor is established by computational fluid dynamics（CFD）, and the coolant flow characteristics in the sub-channels caused by wire-wrap are studied. The results show that the coolant flow in the sub-channels is periodic, and the period is one pitch（100 mm）. The coolant flow in the central sub-channel is affected by the three wires of adjacent rod bundles, and the mixing effect of the wires is stro nger and the flow is more stable. The maximum transverse flow is 1.74 m/s, and the position of the maximum transverse flow varies with the winding position of the spiral structure. This paper provides a reference for further optimization design of annular fuel assembly for the sodium-cooled fast reactor, and has certain research significance.