In order to solve the 3D eddy current induced in curved conductors under varying magnetic fields, an improved distributed current source model was proposed, with the boundary conditions and potential gradient operations re-derived by considering the characteristics of the hexahedral conductor element. A comparative analysis with the finite element model was presented. The results show that the simulation outcomes of the improved distributed current source model align closely with those from the finite element model. Furthermore, the proposed model can more accurately predict the disturbance magnetic field caused by defects during scanning. It is concluded that the proposed model is reliable for solving related physical field problems and holds strong application potential in the field of defect detection.