Abstract: A compression test was done in combination with induction EMF (electromotive force) to investigate the relationship between the EMF variable e and compressive stress σ, taking the D25 mm HPB 235 and HRB 335 steel bars as specimens. The specimens were passing through an AC induction coil and a tiny EMF was produced axially in the steel bar. Then the specimens were compressed by a hydraulic press. Testing results showed that the EMF e decreases with the increasing stress σ, but a increases with the increasing EMF increment Ae, and the relationship between the two variables, i.e., Ε and σ, or σ and ΔΕ, can be expressed respectively by a linear fitting equation. The stress obtained from the induction EMF measured was compared to that obtained from the strain measured one by one, from which the relative mean error was 2.94%. According to the Biot and Savart Law, the reason why the axial current component Ih in the induction coil winding obliquely around a specimen forms a traverse magnetic field Bx was explored.