Copper indium sulphide films were deposited by the pulse plating technique with different OFF times in the range of 5s – 30s and at a constant current density of 5 mA cm-2. The films exhibited single phase copper indium sulphide. The grain size increased with decrease of OFF time. Optical band gap of the films increased from 1.44– 1.497 eV with decrease of OFF time. Optical constants (refractive index, n, and extinction co-efficient, k) of the films have been obtained in the wavelength range 800 - 1700 nm by using spectrophotometric measurement. The obtained results concerning the absorption index yield the energy gap in addition to the type of the allowed optical transitions. N/m* ratio has been obtained from refractive index data. The dispersion of refractive index is analyzed by using a single oscillator model.