Abstract: The complexity of pressure fluctuation dynamics in submerged circulative impinging stream reactor (SCISR) with different rotating speeds was studied by using the multi-scale and R/S analysis method.The Daubechies second order wavelet was firstly used to decompose pressure signals at different rotative speeds to 1—9 scale detail signals and scale approximation signals.Then, Hurst analysis was used to analyze multi-fractal characteristics of different scale signals.By analyzing the signal profile of different scales, different fractal structures at different scales were found, and there remained the similar trend with increasing rotating speed.Besides, there were some deterministic non-periodic components in the system and similar energy exchange between particles caused the diffusion of turbulence, which was the characteristic of an open system.The vortex with different scales would cause chaos.