Abstract: The wettability of present commercial plastic structured packing surface is poor, and liquid film flow characteristics lacks of systematic study on PP surface with modification or not. Based on polymer surface modification and roughening method, the PP surface wettability against water was improved significantly. Film-forming ratio was increased from about 40% to 95%. Thickness increased remarkably on both edgeson the unmodified PP surface, and the maximum fold was up to 460% compared to average thickness in the center. However, film was spread evenly on the modified surface, and film thickness distribution was uniform along the width direction. Film thickness and wave motion at different liquid flow or gas velocity were also studied. It was found that liquid film fluctuated intensely with low liquid flow or aeration.