Photoelectrochemical behaviour of the SnO2 thin film prepared by ultrasonic spray pyrolysis was studied as a function of deposition time, annealing time and phosphorus content. The photocurrent increased up to 10 min (1.16 Cim) with deposition time and then decreased. When the SnO2 thin film was annealed for 10 min at 400 degrees C in air, the maximum value of photocurrent was obtained. When phosphorus was added to the SnO2, photocurrent was decreased continuously with increasing phosphorus content.