For the complexity of fault reasons of vibration diagnosis of extrusion press hydraulic cylinder and the influence of noise, the fault reason and the vibration mechanism of the hydraulic cylinder were analyzed, the vibration information model was founded.Through the research of characteristics analysis of vibration signals, and the time domain and frequency domain were analyzed. the relation and rule between vibration and diagnosis of extrusion press hydraulic cylinder were discussed.At last, a vibration diagnosis example was given. The analysis result lay a fondation for realizing the fault diagnosis based on the vibration of the hydraulic cylinder.