Hollow fiber carbon membranes (HFCMs) were prepared from deacetylated cellulose acetate precursors using a multidwell carbonization protocol. FTIR, scanning electron microscopy, and thermogravimetric analysis−mass spectrometry were employed to characterize the HFCMs. Gas permeation tests were conducted with single gases (H2, CO2, N2, and CH4) as well as gas mixtures. The single-gas test results indicated that the molecular sieving mechanism dominated in the carbon membrane separation process. The effects and feed pressure on the carbon membrane performance were also investigated. Moreover, the gas-mixture test results indicated that the permeability and selectivity need to be optimized by adjusting the operating conditions (basically temperature) for the membrane process. The aging test result indicates that the permeability of the carbon membrane will decrease over time when it is exposed to the laboratory air.