Abstract: Aiming at special type of propellant for solid rocket motors to detect the flaw of artificial standard and natural type respectively with ultrasonic pulse-echo method, then tests were under taken by the use of ultrasonic defect characters and signal extent to carry out ultrasonic imaging processing. Comparing the natural flaw testing result with X-ray CTs one showed that this method could accomplish linear quantitative non-destruct testing of this type of propellant for solid rocket motors.