Double apron drafting is an important unit in yarn spinning; the motion of fibers during the double apron drafting zone directly determines the quality of the final yarn. In this research, we sought to study how the motion of the fibers and the irregularities introduced during the double apron drafting process were affected by the processing settings and fiber properties. The fiber acceleration point under different drafting conditions was investigated using the tracer fiber technique. The results showed that both the drafting parameters as well as the input sliver properties have a certain influence on the fluctuation of fiber acceleration points, but the difference is small. In addition, the irregularity caused by the fluctuation of the fiber acceleration point during the drafting process (CVFAP) was also calculated under the same drafting conditions based on the irregularity of the input sliver and that of the spun yarn. By comparing the relationship between the CVFAP and fiber acceleration point fluctuation, it was found that the trend of the change between the two is in fairly good agreement. This is consistent with theoretical research and practical experience, and it can prove the accuracy of the fiber acceleration point test results from another aspect as well. Studying the dynamic motion of floating fibers during the double apron drafting process sheds light on the correlation between spinning conditions and yarn quality, which can provide a reference for process optimization.