The NaA and La2NiO4/NaA composite membranes were prepared by means of in situ hydrothermal synthesis. The structure, morphology, separation performance, as well as chemical state and surface composition of a La2NiO4/NaA composite membrane were investigated by means of techniques, such as XRD, SEM-EDX, GC, TPD, XPS, and XAES. When the membrane was applied in a membrane reactor for CH4/CO2 reforming, CH4 and CO2 conversions, and CO and H-2 selectivities were significantly higher than the values observed over a traditional fixed-bed reactor. We studied the effects of the flow rate of sweeping N-2, gas hour space velocity (GHSV), and reaction temperature on the conversions of CH4 and CO2. The carbon deposited on the surface of membrane was studied by means of the TPO-MS technique.