Laser-driven capacitor-coil (LDC) targets provide an effective approach for generating pulsed magnetic fields at the hundreds-of-tesla level in laboratory experiments, which has broad applications in high-energy-density physics (HEDP). However, during intense laser–target interactions, self-generated magnetic fields arising from hot-electron transport, charge separation, and laser-plasma instabilities can significantly overlap, both temporally and spatially, with the magnetic field produced by the coil current. This overlap causes systematic overestimation and ambiguity in B-dot probe-base magnetic-field measurements. To address this issue, a series of comparative experiments were designed and performed on the Shenguang-II laser facility. Under identical laser-driving and diagnostic conditions, three types of targets (insulated, simple coil, and inflected coil) were irradiated. By systematically comparing the time-resolved magnetic signals measured at the same probe location, the contribution of self-generated magnetic fields was experimentally separated from the total signal and quantitatively evaluated. Based on this approach, an experimentally implementable subtraction method was proposed to remove the self-generated magnetic-field component without relying on numerical simulations. Furthermore, combined with an axial magnetic-field decay model based on a finite-length solenoid approximation, the coil current and the on-axis magnetic field at the coil center were reconstructed. The results show that, after subtracting the self-generated magnetic field, the extracted peak field reaches several hundred Tesla with a more physically reasonable energy conversion efficiency. The method also reveals distinct temporal evolution features of different coil configurations, providing deeper insight into magnetic-field generation and transport processes. This work establishes a practical and reliable experimental methodology for decoupling overlapping magnetic-field components, significantly improving the accuracy of pulsed magnetic-field diagnostics. It provides a new pathway for precision magnetic-field measurements in magnetized indirect-drive inertial confinement fusion and HEDP studies.