Recurrence plots analysis was to the pressure fluctuation signals with chaos and fractal characteristics in the gas-solids recycled fluidized bed. The relationship between characteristic parameters of recurrence plots and the largest Lyapunov exponent was studied and it was concluded that the characteristic parameters of recurrence plots could reflect the extent of chaos. The change of the characteristic parameters in different styles of fluidized bed was investigated. The characteristic parameters increased or decreased swiftly in the styles of bubbling bed and fast fluidized bed

and kept steady in the styles of fixed bed

turbulent bed and pneumatic conveying bed. Recurrence plots could also indicate the style of fluidized bed.