Abstract: The tensile and compressive stresses of demagnetized specimens made of Q235 steel were tested, and magnetic signal variation characteristics under different tensile and compressive stresses were continuously recorded using a magnetic memory on-line monitoring system. The results demonstrate that the resultant magnetic field first decreases and then increases induced by tensile load and becomes stable when approaching and exceeding 0.3 times the yielding strength of the material, while the resultant magnetic field induced by compressive stress rapidly decreases in the initial stage and then fluctuates. The model for J-A magnetomechanical effect was improved by introducing different stress demagnetization terms caused by tensile and compressive stresses, and the simulation results are consistent with the experimental data, which can be used for theoretically explaining different mechanisms induced by tensile and compressive stresses.