The utility model discloses a compensation leakage current's current transformer error detection device, include: primary winding, iron core I, iron core II, secondary winding, compensating winding, detecting element, the control unit, power amplifier unit, characterized by: the stepup transformer output links to each other with the primary winding, current booster output and primary winding linkto each other, constitute doublestage current transformer by primary winding, secondary winding, compensating winding, iron core I and iron core II, and primary winding, secondary winding be around oniron core I and iron core II, and compensating winding winds on iron core II, secondary winding links to each other with detecting element behind impedance Z, and power amplifier unit is connected todetecting element connection control unit, the control unit, and power amplifier unit connects compensating winding. The utility model discloses a current transformer error -detecting in -process leakage current's under the simulation operation operating mode compensation.