Differential pressure fluctuation measurements were conducted in a gas spouted bed of 120 mm in diameter at different. axial and radial positions. Hurst's rescaled range analysis of the differential pressure fluctuation signals was successfully employed to recognize different flow regimes, i.e. packed bed, stable spouting and unstable spouting, and characterize their transitions. Obvious two-phase behaviour, as suggested by two Hurst exponents, was observed in the stable spouting regime. It had also been found that the spouting behaviour in deeper spouted beds was significantly different. from that in shallow spouted beds. The influences of measurement location and bed height on the Hurst exponents were discussed.