Fluorescent probe quantum dots have a wide application prospect in the fields of biomarker, cell migration tracer and on-line imaging. Magnetic nanoparticles have great advantages in biological fields such as magnetic resonance imaging, drug loading and cell detection. By combining magnetic nanoparticles with quantum dots, magnetic nanoparticles with fluorescence effect and superparamagnetic and fluorescence properties are obtained, which realizes the magnetic field control and fluorescence tracing of particles moving in the molecule. Most fluorescent magnetic nanoparticles have core-shell structure. The shell must be biocompatible and non-immunogenic to prevent the agglomeration of particles while minimizing non-specific interactions with proteins, cells and other components of the biological medium.