This paper mainly introduces the principle, implementation process, and imaging effect of ultrasonic phased array 3D real-time imaging. Firstly, how to generate volume data for 3D imaging with ultrasonic phased array detection data is introduced. Then the 3D imaging method of ultrasonic phased array based on volume rendering is introduced. Finally, the realization effect of phased array 3D real-time imaging is demonstrated through the instrument equipment of Guangzhou Doppler company, including the realization of 3D real-time imaging of phased array by scanning linear array probe and full focus 3D real-time imaging by using matrix array probe.