In order to interpret the effect of semiconductor thickness and annealing temperature on the electrical characteristics of Al/nCdTe/Au Schottky barrier diodes (SBDs), the forward and reverse bias current density-voltage (J-V) characteristics of these SBDs have been investigated in dark. Both of the values forward and reverse currents have decrease with increasing annealing temperature as well as the increase of thickness. The ideality factor (η), saturation current density (J s ) and the barrier height (Φ B ) were calculated using J-V plots. Also series resistance (R s ), shunt resistance (R sh ) has been calculated by R-V plots. The measurements showed that these parameters are affected by annealing temperature and the change in the thickness.