The ultrasonic wave generation and propagation were modeled to simulat
e an ultrasonic test. In order to make the wave generation model of an
angle probe, sound pressure distribution of the wave generated from t
he probe was analyzed by the ultrasonic visualization method. Ray mode
ling is proposed for ultrasonic wave generation and propagation. In th
is model, the sound pressure was expressed as the density of the ray a
nd the reflection coefficient of the ultrasonic beam. The reflection a
nd mode-conversion of the ray were drawn by Snell's law. Simulation pr
ograms of ultrasonic testing for butt weld joints are built using this
ray modeling on a personal computer. Simulation results for scatterin
g the ultrasonic wave from the defect and A-scan display in ultrasonic
testing agreed with the actual experimental results.