The invention provides a nitrogenous active carbon fiber bundle or active carbon fiber fabric and a preparation method of the nitrogenous active carbon fiber bundle or the active carbon fiber fabric. The nitrogenous active carbon fiber bundle or the active carbon fiber fabric is prepared through the following steps: putting pre-oxidized fiber into an activation furnace for carbonization, and at the temperature of 800-1000 DEG C, using the composite activator composed of the NH3/N2 gas mixture and vapor to activate the carbonized pre-oxidized fiber, wherein in the NH3/N2 gas mixture, the volume ratio of NH3 to N2 is (1/4)-1, and the volume ratio of the vapor to the gas mixture is 1/2; the specific surface area of the prepared nitrogenous active carbon fiber bundle or the prepared active carbon fiber fabric is 800-2000 m<2>/g, and the nitrogen content is 2.5-9 wt%. According to the invention, nitrogen is introduced to the active carbon fiber bundle or the active carbon fiber fabric, so that the property of adsorbing sulfur-containing pollutants of the active carbon fiber bundle or the active carbon fiber fabric is remarkably improved. The nitrogenous active carbon fiber bundle or the active carbon fiber fabric has the characteristics of simple preparation technology, low cost and capability of requiring no follow-up modification, and facilitates practical application.