Abstract: A kind of Ni/C composite material,in which nano nickle particles were uniformly distributed in carbon matrix,was prepared by pyrolysis of Ni-exchanged cation exchange resin（Ni-PAA）.The effect of pyrolytic conditions on the morphology,size of nano nickel particles in Ni/C composite material was studied by means of X-ray diffraction（XRD）,Transmission Electron Microscope（TEM）.The results show the particle size of nano nickel in Ni/C can be controlled by pyrolytic conditions;the particle size increases as the pyrolytic temperature and the holding time increase.Magnetic tests show that Ni/C-500 is superparamagnetic,while Ni/C-600,Ni/C-700 are ferromagnetic.The remanence and the coercivity at room temperature of Ni/C-600 and Ni/C-700 are higher than those of the corresponding micrometer nickel powders and bulk nickle,while the saturation magnetization is lower than those of micrometer nickel powders and bulk nickel.