Tin films were electroplated on BAg50 CuZn brazing filler metal substrate using sulfate salt electrolyte. The effect of current density, bath temperature, electrode distance, ultrasonic power and frequency on resistance of tin electroplating electrolyte were analyzed. The better conditions of electroplating tin on AgCuZn brazing filler metal were obtained. The surface morphology of tin electroplating coating was examed. The results indicate that the electrolyte resistance increase with increasing of current density and ultrasonic frequency. The resistance decreases firstly and then increases with increasing of electrode distance. A smooth and uniform surface morphology of tin electroplated film is obtained under the better conditions.