As a current sampling device of singlephase intelligent watthour meter, manganesecopper shunt will produce inductive current under the interference of external magnetic field of power frequency, which will affect the accuracy of watthour meter measurement. In this paper, an optimal design method of induced current of manganese copper shunt is proposed based on robust design theory. Firstly, the basic physical principle of induced current produced by manganesecopper shunt under the interference of power frequency magnetic field is analyzed theoretically, then the simulation model of manganesecopper shunt is established based on Flux software. Afterwards, design of experiment (DOE) based signal noise ratio (SNR) analysis is carried out to rank the influence factor for induced current. Then, the optimal design of manganesecopper shunt is carried out based on Taguchi robust design method. Finally, the induced current before and after optimization is compared by Monte Carlo simulation consistency evaluation. It is proved that the robust design method is suitable for improving the magnetic field interference ability of the manganese copper shunt.