Abstract: The pre-oxidized nonwoven was carbonized and activated in the steam with one step method.The experiment was carried out with experimental apparatus made in the laboratory.There are four factors that influence the iodine adsorption capacity and yield of the produced activated carbon fiber(ACF) needle felt,they are activation temperature,activation time,steam flow rate,and the raising rate of temperature.The optimum technology of the one step steam carbonization-activation experiment was obtained with orthogonal experiment.The influences of the four factors on the results were revealed with single factor experiment.