For microwave remote sensing applications over ocean a precise knowledge of dielectric and radiative Properties of water is required. In present work, spatial and temporal variability of the complex permittivity and refractive index , as well as reflectivity of Persian Gulf water for normal incidence, at L-Band (1.4 GHz), is studied by using an empirical model. The calculations results indicate a relatively significant spatial and seasonal variability in the dielectric and radiative properties of the Gulf due to large variations in temperature and salinity of surface water. The mean real refractive index n over the Gulf surface water varies from a minimum value of 7.295 in December to a maximum value of 7.875 in June with annual mean of 7.581.Theextinction coefficient k reaches maximum value of 2.036 in June and minimum value of 1.303 in January and its annual mean over the Persian Gulf is 1.674.