The ultrasonic wave generation and propagation were modeled to simulate an ultrasonic test. In order to make the wave generation model of an angle probe, sound pressure distribution of the wave generated from the probe was analyzed by the ultrasonic visualization method. Ray modeling is proposed for ultrasonic wave generation and propagation. In this model, the sound pressure was expressed as the density of the ray and the reflection coefficient of the ultrasonic beam. The reflection and mode-conversion of the ray were drawn by Snell's law. Simulation programs of ultrasonic testing for butt weld joints are built using this ray modeling on a personal computer. Simulation results for scattering the ultrasonic wave from the defect and A-scan display in ultrasonic testing agreed with the actual experimental results.