Abstract: To study the propagation regularity of multi-array-elements ultrasonic focusing wave in solid, the author developed the multi-channel dynamic photoelasticity imaging system. By exciting each element of the ultrasonic array transducer with independent phase delay, this system can produce flexible, controllable synthesized sound beams, excite focusing sound wave whose focus is controllable in solid and simulate sound beam scan of ultrasonic phased array technology. By using dynamic photoelasticity technique, we can observe the acoustic propagation of ultrasonic focusing wave in solid. The system realize ultrasonic focusing sound field visualization, and the ultrasonic focusing wave theory of materials testing is verified by the visual experimental means, which has important guiding significance in ultrasonic nondestructive testing.