Conveying solid particles through pneumatic pipes is widely used in various industrial processes. In large-scale pneumatic conveying pipelines, the particles are unevenly distributed in the pipeline and the particle flow state is complex. To accurately characterize the flow parameters of the particles in the pipeline, this article proposes a measurement method integrating the electrostatic and acoustic emission sensors. To obtain the velocity and relative volumetric distribution of particles in localized areas on the pipe crosssection, the cross-section of the square-shaped pipe with a side width of 200 mm is divided into 16 electrostatic signal sensing zones and 4 acoustic emission signal measurement areas. Experimental tests are conducted under 30 different conditions with various particle velocities and mass flow rates. Experimental results show that the particle distribution is inhomogeneous in the large-scale square pipe cross-section, and the velocity distribution is consistent with the characteristics of the asymptotic pipeline flow. Based on the analysis of mass flow rate distribution considering the local particle velocities, the relative mass flow rate distributions of the particles represented by the RMS values of electrostatic and acoustic emission signals vary in the same trend.