The current-voltage (I-V) characteristics of Au/n-GaAs (MS) Schottky diodes were investigated in the temperature range of 300-400 K. By using the thermionic emission (TE) theory, the forward bias I-V characteristics are analyzed to estimate the MS Schottky diode parameters. The estimated zero-bias barrier height (Phi(Bo)) and ideality factor (n) considering TE theory show strong temperature dependence. While the n decreases, the Phi(Bo) increases with the increasing temperature. The values of the n and Phi(Bo) vary from 1.30 and 0.57 eV at 300 K to 1.12 and 0.66 eV at 400K, respectively. Furthermore, the temperature dependence of energy distribution of interface states (N-ss) was obtained from the forward bias I-V measurements by taking the bias dependence effective barrier height (Phi(s)) into account. The Nss decreases with the increasing temperature. In addition, the values of series resistance (R-s) were determined using Cheung's method. The results show the presence of thin interfacial insulator layer between the metal and semiconductor.