An experimental study is carried out for a swirling flow pneumatic conveying system in a horizontal pipeline in terms of the pressure drop and solid flow patterns. The test section consists of a pipeline 13m in length with an inside diameter of 80mm. The three inital swirl numbers in the range of 0.58 to 1.12, the average gas velocity from 10m/s to 23m/s and the solid-gas ratios ranging from 3.5 to 14 were investigated. Polyethylene pellets of 3.1mm were used as the solids conveyed. It is found that in the lower gas velocity range, the pressure drop and the gas velocity at the pressure drop minimum for swirling flow pneumatic conveying were lower than those for axial flow pneumatic conveying. The fluctuation of wall static pressure of swirling flow pneumatic conveying decreases compared with axial flow pneumatic conveying.