Ni-B amorphous alloy particles were selectively loaded inside and outside of carbon nanotubes (CNTs) to form a series of Ni-B/CNTs amorphous alloy catalysts. The confinement effects of the CNTs on the physicochemical properties of Ni-B/CNTs were investigated. The results show that compared with external loading, the Ni-B active components after internal loading were subjected to the confinement effect, which better inhibited the growth and aggregation of Ni-B particles, forming smaller-size Ni-B particles, and improved the thermal stability of the Ni-B amorphous alloy. Moreover, the Ni-B particles confined in the channels can more efficiently activate hydrogen. During the m-chloronitrobenzene hydrogenation, the Ni-B/CNTs with Ni-B internal loading showed higher catalytic hydrogenation activity than that for Ni-B external loading. High-temperature treatment caused a decrease in the catalytic activity, but the internal loading improved the stability of the catalysts. The internal loading method could effectively reduce the loss of the active component, which contributed to improving the stability of the catalyst.