The singlet state potential energy curve of the reaction NI (d101S) +CH4→NICH2+H2, the electronic and geometric structures and vibrational frequencies of all intermediates and transition states in the reaction path were studied by B3LYP method. In the reaction, an atom-molecule complex NiCCH4acting as precursorin the breaking of C-H bond was predicted. For NiCH4, a frequency of 2988cm-1 is typical of methane molecularly adsorbed on Ni.Frequencies of 2531 and 2438cm-1are indicative of the formation ofa C-H...metal bond and a frequency of 355-1is typicalof Ni-CH4 stretching mode.A nickel hydrdo-methyl complex HniCH3is frmed upon the very low bamier in sertion of Ni0into a C-H bond of CH4. For HNiCH3,frequencies of 2980 and 2853cm-1 are representative of CH3 coadsorbed with H on Ni, and a frequency of 565cm-1 is indicative of the HNi-CH3 stretching mode. Adihydrogen complex of atom ni ckel carbene (H2) NiCH2 proceeds from the migration of a-hydrogen from carbon to metal with considerably large barrier,indicating that this is the rate-determining step in the whole spectively.Sybsequently, the whole reaction .For (H2) NiCH2, frequencies of 3344 and 694cm-1 are characteristic of H-H and (H2) NI-CH2 stretching modes respectively.Subsequently,the final products NiCH2 and H2 evolve after the elimination of H2 fron the transition-metal center.For NiCH2, a frequency of 754cm-1 is assigned to the Ni-Ch2 stretching mode. For all intermediates and transition states in the reaction path,the electron transfer is exclusively from nickel to carbon. Ingeneral, the overall reaction is mildly exothermic by1.6KJmol-1relative to Ni(d101S)+CH4reactants.