To solve the problems of the traditional packings, such as high pressure drop, mal-distribution and short liquid residence time, a helical flow structured packings was proposed. Two different flow patterns, liquid-bridge flow and liquid-drop flow were identified when the width of the channel of the helical string was adjusted. Moreover, the characteristics of the helical liquid-bridge flow including maximum liquid loading, mean thickness of liquid film, mean residence time and effective specific surface area, were examined. And the separation efficiency was studied by the lab-scale distillation column. In comparison, the effective specific surface area of the helical flow type packings is almost as large as the traditional B1-350Y structured packings, but with thinner liquid film, longer liquid residence time and finally higher separation efficiency. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 3360-3368, 2018