The invention belongs to the technical field of cable detection and relates to a parameter determining method for a built-in metal foil partial discharge sensor. According to the parameter determiningmethod, a parameter determining platform is adopted. The method involves carrying out a key parameter determination test, carrying out a supplement test and the like. The parameter determining methodis based on a physical observation experiment test and does not involve the equivalent simplification of a model. The parameters of the metal foil partial discharge sensor which are determined by themethod have high applicability. According to the method, comparison experiments are carried out from a plurality of dimensions; determined metal foil electrode parameters enable the partial dischargesensor to extract more comprehensive signals, so that the accuracy of later-stage partial discharge analysis is improved.