The hydropower stations with high water head and long diversion tunnel have some characteristics such as long period of oscillation, large oscillation range and slow-attenuation wave in the process of hydraulic transient. The vibration of Francis turbine's head cover can reflect these characteristics.Based on a hydropower station with high water head and long diversion tunnel, the paper described the vibration of its head cover with a combination method of wavelet and wavelet packet analysis. The results show that the strong vibration resonance of head cover results from the three factors such as flow pulsation, tail water vortex and water hammer,for their frequencies are close in the hydropower station with high head and long diversion tunnel. Flow pulsation and tail water vortex are the most main factors which cause the vibration of head cover. This paper also proved that the method combing wavelet with wavelet packet is a better tool in the treatment of vibration signal of hydropower station.