The aim of this study was to investigate the displacement of the thoracocervical spine occurred during the application of the thoracic PA mobilization. Forty-one asymptomatic male subjects (20-30 years) were recruited. The spinal displacement of C3, C5, C7, T2, T4 and T6 was investigated during the application of a set of the central PA mobilization grade III to T6 by a motion capture system. Descriptive statistics were used to analyze the distance of the spinal displacement and Spearman rank correlation coefficient demonstrated negative correlation (rs=-1) between spinal displacement and spinal levels. The results indicated the downward trend in spinal displacement when the distance far from T6 spine increased. It showed that the mobilization force could be transferred from local spine along the spinal column to remote area. Therefore, these findings provide possible evidence to explain the mechanism of how thoracic spinal manipulative therapy affected neck pain reduction.