We have successfully prepared a novel Ni/SiO2 magnetic catalyst, and put it into the process of one pot synthesis of imines directly from aromatic nitro compounds and aldehydes for the first time. The catalyst has been characterized by XRD, IR, TEM, SEM, TPR, H-2-TPD and XPS. The prominent merits of the Ni/SiO2 magnetic catalyst passivated with a gas mixture are that it can be stored safely in air below 423 K and needs no activation before use. In the catalytic test, most conversion and selectivity is almost up to 100%, and it is found that the catalyst is highly efficient, stable, and reusable for the synthesis of imines.