Background <p>Wire and arc additive manufacturing (WAAM) enables rapid production of large-scale metal components, but inherent anisotropy caused by directional solidification remains a critical challenge. The piezomagnetic-mechanical coupling characteristics in WAAM-produced metals and their directional dependencies are poorly understood.</p> Objective <p>This research aims to investigate the correlation between piezomagnetic anisotropy and mechanical properties in low-carbon steel produced by WAAM under tensile stress.</p> Methods <p>ER70S-6 steel specimens were fabricated via robotic WAAM and extracted at five angles relative to the deposition direction. Monotonic tensile tests with synchronized piezomagnetic measurements were conducted using the universal testing machine and fluxgate magnetometer. Microstructural characterization was performed via optical microscopy and electron backscatter diffraction (EBSD) to analyze grain morphology, phase distribution, and crystallographic orientation.</p> Results <p>The results show that as the angle between the tensile loading orientation and the deposition orientation increases, the elastic modulus, ultimate tensile strength, and ductility decrease progressively. The piezomagnetic behavior mirrors these mechanical properties, with more significant magnetic induction changes observed in the direction parallel to the deposition layers. Three characteristic parameters were defined to describe the piezomagnetic properties of the WAAM material, and a linear relationship between these parameters and the printing direction of the specimen was established.</p> Conclusions <p>The directional alignment of deposition layers governs both mechanical and magnetic responses through microstructural anisotropy. Piezomagnetic analysis provides enhanced sensitivity for quantifying WAAM material anisotropy, offering a non-destructive diagnostic method to evaluate directional performance in additively manufactured components.</p>