Abstract: The flow-induced vibration mechanism of the fuel rod fixed by wrapped wire under the influence of leakage flow is investigated by the way of experiment and numerical simulation. According to the CFD and experimental results, it is found that the wrapped wire would play a role of increasing the cross flow mixing effect in the flow channel, which would have a significant influence on the stability of fuel rod. Based on experimental and numerical results, it is found that when flow rate is low, the vibration of rods is mainly caused by the turbulence, but as flow rate increases, the effects of leakage flow become obvious. Effect of vibration leakage flow of the fuel rods are divided into two kinds: changing the vibration energy distribution in the frequency domain, so that the high frequency energy of vibration is increased; increasing the RMS value of vibration displacement of fuel rod.