Abstract: The pipelines of the EH oil system of the steam turbine are connected to the oil supply system, emergency shutoff system and the implementing agency to form the entire circuit. As the transmission channel of the oil medium, once a leak occurs, it will directly cause the unplanned outage of the generator set, which will result in huge losses of economic benefits and social benefits for the enterprise. A few typical cases of EH oil pipeline leakage occurred in thermal power generation units recently. In this paper, several types of failure mechanisms that are common to EH oil pipelines were summarized from the perspective of metal materials. Combined with each typical case, the failure analysis process and its focus were introduced briefly. And from the technical supervision point of view, the paper puts forward the governance and preventive measures importantly, specific to the corresponding inspection methods and inspection contents, which fit the scene for reference.