Abstract: The offline oil chromatography detection of the high-voltage bushing in the network side of converter transformers exists the shortcomings of delayed diagnostics and discontinuous data, resulting in the internal faults being unable to be found in time.Aiming at the above problem, a kind of insulation online monitoring method for high voltage bushing in the network side of the converter transformers is proposed.The application on site result shows that this method, by collecting the leakage current from the bushings’ end screen, reflects the operational status of the bushings, thus enabling online diagnosis and early fault warning of the high-voltage bushings in the network side of the converter transformers.