The invention discloses a household-transformer relation recognition method and system based on capacitor switching. The method comprises the steps that firstly, the characteristics of generating a current signal in a capacitor switching mode in an actual power grid are analyzed; secondly, a sampling frequency and a switching frequency point are determined according to power grid load current characteristics; thirdly, a switching signal is generated, and a duty ratio is determined; fourthly, the switching signal is coded, and it is determined to send a characteristic code; fifthly, noise processing and signal enhancement are performed in a de-loading mode; and sixthly, a secondary-side current of a transformer is sampled and analyzed in real time, a household-transformer relation is determined by performing Fourier analysis and characteristic code matching on a switching frequency point signal, and a corresponding phase is determined according to the magnitude of the three-phase current. By adopting the method and system to perform household-transformer recognition, through de-loading processing, noise interference can be effectively weakened, and characteristic frequency point intensity can be effectively enhanced; and the method and system have the advantages that the recognition effect is good, the switching current is small, operation is simple, less heat is emitted, the volume is small, and miniaturization is easy to realize.