The flow characteristics of multiphase gas-solid flow in a pneumatic conveyor were investigated experimentally and numerically. Experiments were conducted to acquire the static pressure at certain cross-sections of a fine powder pneumatic conveying pipeline with a length of 26 m and an inner diameter of 53 mm. The conveyed material was fly ash with a mean particle size of 30 micron and the solids loading ratio was in the range of 20 to 70. Experimental data under nine different flow conditions were obtained and analysed. A numerical study of gas-solid flow was undertaken by means of commercial CFD software Fluent. The simulation was performed using the Euler-Euler approach, accounting for four-way coupling. The calculated results of pressure gradient were found to be in good agreement with the measured data.