step S1, for each stator slot (1) in the aircraft generator, wrapping one semiconductor layer (4) on a surface of an external insulation layer (3) of each copper conductor (2) in the stator slot (1);

step S2, for each semiconductor layer (4), partitioning the semiconductor layer (4) to obtain a plurality of zones, disposing a resistor-inductance branch network in each zone, and connecting the resistor-inductance branch networks to form an insulation failure detection circuit;

step S3, supplying power to a three-phase winding of the aircraft generator from an external power source;

step S4, determining whether an unearthed voltage is present in four end corners of the insulation failure detection circuit;

if not, returning to perform the step S3 of supplying power to the three-phase winding;

if yes, outputting a detection result indicating an insulation failure and collecting an insulation failure position with potential change and a potential difference in the insulation failure detection circuit as a positioning result for outputting.