Abstract Surface plasmon play a crucial role in the fields of microscopic imaging, spectroscopy, semiconductor devices, nonlinear optics, and so on. However, there is still no robust method for characterizing the surface plasmon at the nanoscale. Here, an approach for the characterization of surface plasmon at the nanoscale was proposed by imaging the distribution of surface plasmon-induced electromagnetic field using magnetic force Spectroscopy microscopy technique, and the visualization of its induced electromagnetic field is demonstrated by combining magnetic force spectroscopy with a 3D reconstruction algorithm. Furthermore, an inhomogeneous electromagnetic field caused by nanostructure defects is identified by 3D imaging. The experimental method and results are of great significance for the study of surface plasmon and their effect at the nanoscale. This technique proves invaluable for investigating surface plasmon and has great prospects of testing and application for plasmon excitation, quantum dots, and nanosensor.