Abstract: The ceramic bodies (including origin, green and gross bodies) were effectually detected with nondestructive ultrasonic technique
in the ground of 20～50MHz operating frequency, by means of the directly coupling method with a delaying block.

The microstructural anomaly of materials, which may appear in each of the preparing steps can sensibly be responded by the acoustic
parameters (velocity and attenuation). The choice of optimum operating frequency and coupling condition is necessary for a creditable detection
of green and gross bodies with defect by using ultrasonic technique.

Key words: ceramic green body, ultrasonic technique, nondestructive detection