The motion of wireless capsule endoscopes (WCE) in the gastrointestinal tract is complex and variable. Measuring its motion patterns accurately is crucial for optimizing diagnostic, therapeutic procedures and improving diagnostic accuracy. To gain a deeper understanding of the motion patterns of WCE in the gastrointestinal tract, particularly its behavior in different regions. A simulation measurement system based on magnetic localization technology is proposed in a laboratory environment. We designed a cylindrical-conical-cylindrical structure simulation device. The free fall motion of soft hydrogel granules is designed to mimic fluid motion in the gastrointestinal tract. A hard-targeted pellet with a permanent magnet simulated the WCE. It measured parameters such as trajectory, vertical velocity, vertical acceleration, and attitude angle of the targeted pellet during its drop at different initial positions in a silo during unloading in a soft granules environment were measured. The experimental results reveal the motion characteristics of a hard pellet in a silo during unloading in a soft granules environment, in the specific wide channel region, as well as in the transition region from the wide channel to the narrow channel. These findings provide data references for understanding the dynamic behavior of WCE in the gastrointestinal tract, thereby aiding in optimizing WCE design and enhancing its clinical efficacy.