A novel approach based on the passive acoustic emission (AE) monitoring technique has been established for analyzing particle-wall collision and friction separately in the present work. Using power spectrum density analysis, the main frequency of AE signal caused from particle-wall collision is found to be higher than that generated by particle-wall friction. Besides, a method for quantitatively extracting the information on particle-wall collision and friction has been set up by wavelet transform analysis. On the basis of these analyses, a theoretical approach has been established for relating the AE signals and solids loading ratio in a vertical pneumatic conveying pipe. The model predictions are verified using experimental data and are in good agreement. Particle mass flow rates obtained using this model give errors less than 6.62%. Conclusions can be drawn that the AE technique has great potential in the measurement of hydrodynamics in pneumatic conveying as well as similar particulate processes.