Abstract: Disclosed is a clamp-on-type ultrasonic concentration metering system and method. The clamp-on-type ultrasonic concentration metering system includes an ultrasonic sensor portion and a concentration meter. The ultrasonic sensor portion is attached to an outer wall of a pipe through which a fluid to be measured flows and that transmits and receives an ultrasonic signal through a wall of the pipe. The concentration meter measures a concentration of a substance according an intensity of the ultrasonic signal that is received after passing through the wall of the pipe, the fluid to be measured, and the wall of the pipe by means of the ultrasonic sensor portion.