Abstract The structral morphology of metal catalyst Ni in the synthetic diamond was measured by using the fluorecence EXAFS technique. The nickle impurities found exist as fee structure, which is similar to the pure metal Ni. The results obtained from the amount of C atoms coordinated surround Ni and the dilation of Ni-Ni distance show about 9 at-% carbon in the metal Ni matrix which is much more than the limit of earbon solubility 2.7 at-% in metal Ni at normal pressure. The coordination number of Ni in diamond found is less than that in pure metal. This shows that the nickle in the diamond distributes as small particles with dimension about 20?.