Abstract: The wire wrap on the surface of the fuel rods of the sodium cooled fast reactor can strengthen the transverse flow of the coolant between the channels, reduce the unevenness of the temperature distribution in the assembly box, and improve the safety of the reactor. Different types of wire-wrap mixing models are used in sub-channel codes to simulate the effect of wire wrap on simulation results in an assembly. To study the influence of different wire-wrap mixing model on the simulation result of flow and heat transfer, based on the Mikityuk convective heat transfer model and the Cheng-Todreas flow pressure drop model, sub-channel analysis method has been established with the forced cross flow model and the wire-wrapped turbulent mixing model respectively. The results are compared with the data of FFM-2A experiment carried out by ORNL and results of other sub-channel codes. It is found that in the case of low flow rate, the two methods’ simulation result fits the flow and heat transfer of the wire-wrapped assembly well. And in the case of high flow rate, the method of the forced cross flow model is consistent with the experimental results, while the method of the wire wrapped turbulent mixing model overestimates the temperature at the outlet of channel center.