Because there is a high demanding on stability and safety for highspeed railway, bridge vibration monitoring radar is designed using interferometry and phase inversion techniques. It has advantages such as simple structure, operated easily, highprecision and high accuracy. Moreover, it can measure weak vibration in mm levels. Thus, it can solve the problem of complex processes, high cost, low accuracy, and low efficiency of conventional bridge monitoring methods. In addition, it can be applied into highspeed railway bridge monitoring regions. The monitoring experiment of Cool Water Mega Bridge of BeijingTianjin intercity highspeed railway proves that the radar is effective and right. It can not only obtain the realtime deformation of the bridge vibration accurately, but also can acquire the type of bridge vibrations.