This study aims to investigate the effect of seed position on the falling behavior of the fruit valves of Koelreuteria elegans (Taiwan rain tree). To increase seed dispersal distance, plants have evolved diverse fruit structures and dispersal mechanisms. The capsule of K. elegans possesses a wing-like structure that generates aerodynamic effects during descent.In this study, forty intact fruit valves were divided into four groups, with seeds attached at different positions. The airborne duration, horizontal displacement, and falling trajectory were measured.The experimental results showed that the seed position affected the fruit valve’s airborne time and falling path, but had no significant effect on horizontal displacement. When the seed position was asymmetric, the fruit valve exhibited a longer airborne time; under symmetric conditions, valves with seeds closer to the center also had longer airborne durations.Trajectory analysis using Tracker software revealed that seed position significantly influenced the falling path of the fruit valves. These findings suggest that the seed distribution in K. elegans capsules is not random but may serve an ecological function in regulating falling stability or dispersal pattern.Overall, this study enhances the understanding of the aerodynamic characteristics of wind-dispersed plants and provides a valuable reference for further exploration of plant seed dispersal mechanisms.