Ni/C60 granular films were prepared by magnetron sputtering and thermal evaporation techniques with different ratios of Ni atoms to C60 molecules. A high-resolution transmission microscopy analysis shows that Ni nanoparticles are well isolated and embedded in an amorphous C60 matrix. X-ray-diffraction and Raman spectra indicate lattice expansion of Ni particles and charge transfer from Ni to C60, which provide clear evidence that strong interfacial interactions exist between Ni particles and the C60 matrix. Measurements of the surface magneto-optical Kerr effect show that the coercivities (HC) of Ni particles embedded in C60 matrix are enhanced significantly. The film with an average Ni particle size of 3.3nm still presents ferromagnetism with a value of HC of 45 Oe at room temperature. We suggest that the enhancement of HC may be attributed to surface spin disorder of Ni particles induced by the strong interfacial interaction between Ni and C60.