The invention discloses an analog-digital mixed filtering method which comprises the following steps: an analog-digital mixed filtering platform is built, output signals of a device being detected are obtained, the signals are sampled and converted via a high speed A/D collecting card, the signals are processed via a computer, the processed signals are sent to a signal generator for D/A conversion, and the processed signals are analyzed and processed via the computer and then sent to a display device for wave form displaying. Via use of the analog-digital mixed filtering method, simple operation of a detection method can be enabled, complex on-site interference signal processing work can be rapidly finished, requirements for skills of technical personnel can be lowered, an ordinary detection worker can perform detection operation, and working efficiency and accuracy of high voltage electrical equipment partial discharge on-line detection can be improved.