Abstract: The vibration characteristics of converter transformer are closely related to its operating conditions. However, at present, there is a lack of effective research on the vibration laws of transformer and converter transformer during the whole operating period. Consequently, based on the development of the vibration online monitoring system and signal acquisition, combined with theoretical research and online monitoring data analysis, the variation law of oil tank surface vibration of the converter transformer under different operating conditions is explained. Four different vibration stages of the converter transformer are defined in terms of different combinations of current and voltage.Finally, the vibration characteristics under special operating conditions are studied. The research results show that, compared with ordinary power transformers whose vibration is mainly concentrated at the fundamental frequency of 100 Hz, while the vibration of the converter transformer at a specific location is mainly concentrated at 200 Hz and 400 Hz. There are quite differences in vibration under different operating conditions, but the overall vibration changes regularly with the current and voltage. The core condition monitoring should be selected in the Ⅱ vibration stage, and the winding condition monitoring should be selected in the Ⅳ vibration stage. The research results provide an effective applicable range and data support for mechanical condition monitoring and fault diagnosis of transformer based on the vibration signal analysis method, and eliminate errors caused by its own different operating conditions.