A Ni-P amorphous alloy/ceramic membrane with high selectivity and permeability for hydrogen was prepared by a novel technique of local electroless Ni-plating with metal-activated paste. The separation factor obtained is higher for H-2/Ar compared with gamma-Al2O3/ceramic composite membrane. In addition, two kinds of Ni-P alloy/ceramic composite membranes, as-prepared and crystallized ones, were applied to the membrane reactor of ethanol dehydrogenation, and the effect of the reaction temperature, argon sweeping rate and space time on ethanol conversion and yield of acetaldehyde was investigated. The results demonstrated that ethanol conversion in an as-prepared Ni-P amorphous alloy membrane reactor was significantly higher than that in a Ni-P alloy membrane reactor after crystallization, owing to an original structure of as-prepared Ni-P membrane. Meanwhile, the morphology of the membrane was observed by SEM. The crystallized process of non-supported Ni-P alloy membrane was detected by XRD. The surface composition and valence state of the membrane before and after reaction was investigated by XPS.