Composite bed involves an alternative technique in which a layer of micro-fibrous entrapped composite material is added at the downstream end of a conventional fixed bed to strengthen the mass transfer process. In this study, our purpose was to compare the ability of composite beds to remove volatile organic compounds (VOCs) and Freon refrigerants with conventional fixed beds and analyse the effect of relative humidity (RH) on multicomponent organic vapor adsorption on composite beds. This would be used to guide the design of composite beds and their application in air purification. A series of micro-fibrous entrapped activated carbons (MFECs) were prepared using the wet layer paper-making/sintering technologies. The 1,1,1,2-tetrafluoroethane (R134a) and C6H6 breakthrough curves and times on composite beds were systemically evaluated under dry and wet conditions. Results show that under dry condition, due to the enhanced mass transfer, the R134a and C6H6 breakthrough times on composite beds were longer than on fixed beds. Under wet conditions, due to the water vapor competitive adsorption and the difference in organic vapor boiling point, the composite bed prolonged the C6H6 breakthrough time but weakened the R134a breakthrough time. Multicomponent competitive adsorption process (R134a/C6H6) under wet conditions was revealed and divided into six stages including Co-adsorption, H2O and R134a breakthrough, R134a desorption, R134a and H2O adsorption equilibrium, C6H6 breakthrough, and dynamic adsorption equilibrium. These findings indicated that composite beds may improve the breakthrough time of low-concentration C6H6 and lengthen the service life of conventional fixed beds at any RH, thereby displaying potential for use as an application in air purification.