The paper chiefly compares the catalytic activity and stability of nano-sized nickel and Raney nickel in the catalytic hydrogenation of p-nitrophenol.The experimental results show that the catalytic activity and stability of nano-sized nickel are superior to those of Raney nickel under the same reaction conditions. The fresh and used nickel samples are characterized by nitrogen sorption and particle analyzer. The results suggest that particle size,surface structure,etc. may play a key role in determining the catalytic activity of nickel samples.The aggregation of nano-particles would lead to the deactivation of nano-sized nickel,while the jamming of pores would be one of the reasons for the deactivation of Raney nickel.