Structured packing is a good candidate for CO2 capture process because of its higher mass transfer efficiency and lower pressure drop.Now,the challenging problem of CO2 capture and storage demands more and more efficiency equipment.The aim of the present study is to investigate the liquid film characteristics under counter current gas phase and throw some insight into the enhancing mechanism of mass transfer performance in structured packing.A high speed digital camera,non-intrusive measurement technique,was used.Water and air were working fluids.Experiments were carried out for different gas/liquid flow rates and different inclination angles.The time-average and instantaneous film widths for each set of flow parameters were calculated.It is shown that the effects of gas phase could be neglected for lower flow rate,and then,become more pronounced at higher flow rate.According to instantaneous film width,three different stages can be distinguished.One is the constant width of liquid film.The second is the slight decrease of film width and the smooth surface.This kind of character will lead to less interfacial area and deteriorate the packing mass transfer performance.For the third stage,the variation of film width shows clearly chaotic behavior.The prediction model was also developed in present work.The predicted and experimental results are in good agreement. Structured packing is a good candidate for CO2 capture process because of its higher mass transfer efficiency and lower pressure drop. Now, the challenging problem of CO2 capture and storage demands more and more efficiency equipment. The aim of the present study is to investigate the liquid film characteristics under counter current gas phase and throw some insight into the enhancing mechanism of mass transfer performance in structured packing. A high speed digital camera, non-intrusive measurement technique, was used. Water and air were working fluids. different gas / liquid flow rates and different inclination angles. The time-average and instantaneous film widths for each set of flow parameters were calculated. If shown the the effects of gas phase could be neglected for lower flow rate, and, more pronounced at higher flow rate. According to instantaneous film width, three different stages can be distinguished. m. the second is the slight decrease of film width and the smooth surface. this kind of character will lead to less interfacial area and deteriorate the packing mass transfer performance.For the third stage, the variation of film width shows clearly chaotic behavior. prediction model was also developed in present work.The predicted and experimental results are in good agreement.