In the present study, nonlinear hydrodynamic behavior of a circulating fluidized bed with a riser 0.10 m in inner diameter and 10 m in height was characterized in terms of the Hurst exponent and V statistic obtained by the R/S analysis, as well as Mann-Whitney statistic determined by short-term predictability analysis. Hurst exponent, the maximum V statistic and Mann-Whitney statistic were estimated for time series of the local heat transfer rate measured by a hot-wire probe in three radial positions at the height of 6.0 m from the riser bottom. The effects of superficial gas velocity and circulating solid mass flux on the gas-solid flow behavior in the CFB were examined based on the statistics. The Mann-Whitney statistic estimated for the time series was lower than the 99% rejection threshold for the null hypothesis, indicating that the gas-solid flow behavior in the CFB is statistically distinguishable from linearly correlated noise. Radial distributions of the Hurst exponent and Mann-Whitney statistic were found to become flatter as circulating solid mass flux increased. This result indicates that the gas-solid flow structure becomes more uniform and deterministic with increasing circulating solid mass flux. The variation of the maximum V statistic toward circulating solid mass flux appeared to be similar to that of the Hurst exponent.