A stepped copper-bar current measurement apparatus. The apparatus comprises: a circuit board (3), a magnetic induction module (2) and a stepped copper bar (1), wherein the magnetic induction module (2) comprises a first magnetic induction unit (211) and a second magnetic induction unit (212); the side of the stepped copper bar (1) facing the magnetic induction module (2) comprises a first step (11) and a second step (12), which are different from each other; the first magnetic induction unit (211) is located above the first step (11), and the second magnetic induction unit (212) is located above the second step (12); a current to be measured flows through the cross section perpendicular to the stepped copper bar (1); the first magnetic induction unit (211) and the second magnetic induction unit (212) induct, in a differential manner, a differential-mode magnetic field which is generated by said current flowing through the stepped copper bar (1), and generate differential voltage signals and output the differential voltage signals. The apparatus has the characteristics of having an adjustable common-mode magnetic field working point, being applicable to various magnetic induction units, having adjustable sensitivity, realizing electrical isolation between an input and an output, having a strong resistance to common-mode interference, being able to measure alternating currents and direct currents, and having a large current.