The launch site security issues have been became the focus of the world’s research for several decades. Aiming at the filling system, the pipe vibration caused by the liquid hydrogen which flowed through the bend pipe was studied. And based on the computational fluid dynamics, the flow field was simulated according to the numerical simulation method. Then, the changes of flow parameters i.e. pressure and velocity at the bend were observed. The simulation results showed that: (1) the speed and the pressure of the liquid hydrogen would have a sudden change which was caused by flow direction and it would create a vortex which could erode the pipe and lead to the pipe vibration in the region. As a result, the pipe would deteriorate caused by the vortex. (2) the flow field analysis using the numerical simulation method was feasible. And the method provided a flow field distribution directly and design basis for filling system pipes.