Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen were carried out in an experimental test facility with the conveying pressure up to 4 MPa and the solid-gas ratio up to 450 kg·m-3.The influences of conveying differential pressure，gas volume flow rate and superficial velocity on the solid-gas ratio were investigated.The Shannon entropy analysis of pressure fluctuation time series was developed to reveal the flow characteristics.Through the investigation on the distribution of Shannon entropy in different conditions，the flow stability and evolutional tendency of Shannon entropy in different regimes and regime transition processes were discovered.The relationship between Shannon entropy and flow regimes was also established.The results indicated that solid gas ratio and Shannon entropy increased with increasing conveying differential pressure.Shannon entropy was different for different flow regimes，and was able to identify the flow regimes.Shannon entropy analysis is a feasible approach to researching the characteristics of flow regimes and flow regime transitions in dense-phase pneumatic conveying under high pressure.