Aimed to the vibration fault of air-cooling fan in 330 MW direct air-cooling units in Shanxi Youyu Power Plant, the vibration rule of fan, reducer and fan bridge is gained through a series of analyses and tests on fan. The vibration fault of air-cooling fan could be eliminated by some measures, such as the reinforcement of fan bridge, and changing the fan blade number from 5 to 6. These vibration fault treatments and test results could provide references for fan’s design and construction.