The invention discloses a transformer vibration on-line monitoring system. The system comprises vibration sensors, a dynamic signal acquisition device, a computer and a thermometer, wherein the vibration sensors, the dynamic signal acquisition device and the computer which are connected with one another sequentially. Since the transformer vibration on-line monitoring system has no electric connections with a whole electric conduction system, on-line monitoring can be carried out safely and reliably. According to the system, the plurality of vibration sensors are arranged at different positions of the surface of the oil tank of a transformer, so that a best measurement position can be obtained through comparison, and monitoring and analysis can be carried out according to various kinds of states of the transformer, and therefore, a large amount of data can be provided for diagnosis and analysis of the core and winding of the transformer. With the system adopted, accident hidden dangers of the transformer can be found timely; accidents can be avoided; the safety and reliability of the operation of the transformer can be improved; effective implementation of state maintenance can be and promoted; and economic efficiency can be improved. Thus, the transformer vibration on-line monitoring system is not only has important scientific value for the scientific and technological progress of the electric power industry, but also is of great significance for the improvement of the operational reliability and scientific management level of a power system.