With the increasing application of magnetic nanoparticles in targeted therapy and biomedical fields, precise control of their motion in fluids has become a research hotspot. This study, based on the ANSYS-Fluent simulation platform, simulated the motion control of magnetic nanoparticles in microvessels. By applying a rotatable gradient magnetic field, the motion of the particles was controlled to achieve precise targeted positioning. To enhance control accuracy, a PID controller was introduced, which adjusts the magnetic field gradient based on the real-time position of the particles, thereby ensuring stable positioning. During the simulation, the effects of magnetic force and viscous drag on particle motion were considered. The experimental results demonstrate that adjusting the magnetic field gradient can effectively control the motion of the particles, allowing them to remain stable within the target area. This provides strong support for the optimization of magnetic nanoparticle-based targeted delivery systems.