In order to investigate the effects of pre-oxidation conditions on adsorption performance of activated carbon fibers ( ACFs) ,electrospun polyacrylonitrile ( PAN) fiber webs were adopted as precursors for preparing ACFs. Firstly,the webs were stabilized under different pre-oxidation conditions; secondly,the pre-oxidative fibers were chemically activated by high temperature treatment in nitrogen. Pre-oxidation temperature,heating rate,and treatment time are the main factors on affecting the adsorption performance of the ACFs. Scanning electron microscope ( SEM) , differential scanning calorimeter ( DSC ) ,and Fourier transform infrared spectroscopy ( FTIR ) were used to characterize the structure and property of the pre-oxidative fibers,and the dynamic benzene adsorption capacity of benzene of ACFs was measured. The results indicate that the moderate pre-oxidation condition is necessary to prepare the ACFs with better adsorption capacity,and the optimal oxidation conditions are to increase from room temperature to 230 ℃ with a heating rate of 0. 75 ℃·min - 1 ,held at the peak temperature for 30 min. In order to investigate the effects of pre-oxidation conditions on adsorption performance of activated carbon fibers (ACFs), electrospun polyacrylonitrile (PAN) fiber webs were adopted as precursors for preparing ACFs. Firstly, the webs were stabilized under different pre-oxidation conditions; secondly, the pre-oxidative fibers were chemically activated by high temperature treatment in nitrogen. Pre-oxidation temperature, heating rate, and treatment time are the main factors on affecting the adsorption performance of the the ACFs. Scanning electron microscope (SEM), differential scanning The results indicate that the pre-oxidative fibers, and the dynamic benzene adsorption capacity of benzene of ACFs were measured. The results indicate that the moderate pre-oxidation (FTIR) condition is necessary to prepare the ACFs with better adsorption capacity, and the optimal oxidation conditions are to incre ase from room temperature to 230 ° C with a heating rate of 0.75 ° C · min -1, held at the peak temperature for 30 min.