X-ray absorption measurements of 100Å Zr thin films deposited on Si(111) substrates in UHV have been obtained by using a total electron yield detector. Experiments were performed on Zr/Si thin films in order to obtain structural information and find the optimum annealing temperature to produce uniform ZrSi2 epitaxial thin films on Si(111) substrates. A quantitative X-ray absorption fine structure analysis indicates that the films annealed above 650°C form ZiSi2 disilicides, which have the orthorhombic-base centered C49 structure.