The distribution of voidage was statistically studied in a plexiglass bubbling fluidized bed with a constant section. Four statistics, including average, standard deviation, skewness, and kurtosis, were analyzed. The vertical, horizontal, and three-dimensional distributions of voidage with various gas velocities were investigated. The results showed that both the vertical and horizontal distributions of voidage were more discrete for high gas velocities, i.e., the difference between different positions was greater. At the highest gas velocity, both voidage and the bubble size reached the maximum in the upper bed center. The minimum of voidage occurred near the upper bed wall, and the bubble was small both at the bottom and near the wall. The region of the sufficient bubbling fluidization was the maximum region of voidage, while the region of the particulate fluidization was the minimum region of voidage.