In this paper, the current-voltage characteristics of n-CdSe/p-Si heterostructures are analyzed using experimental data and electrical junction characteristics. To develop n-CdSe/p-Si heterojunctions, a wide band gap semiconducting layer of n-type CdSe thin film has been grown on a p-type Si (100) substrate at 100 o C with different thickness by using the spray pyrolysis technique. The IV characteristic of n-CdSe\p-Si heterostructure has been measured in a room in the dark and under illumination (lamp/160 W). Also, the solar cell IV characteristics and efficiency were measured. The characteristic parameters of the structure such as barrier height, ideality factor, and series resistance were determined from the current-voltage measurement.