The large array multi-group scanning ultrasonic phased array system can provide better scanning flexibility, image contrast, increase the diversity of focal law and realize distributed scanning. In order to improve resource utilization, ensure realtime performance and realize distributed scanning under limited resources, it is necessary to study system resource reuse and data processing cooperative scheduling, reduce hardware consumption and avoid signal processing overlapping conflicts, and improve instrument performance. Therefore, the scheduling theory, methods and key technologies of multi-group delay and focus, multi-group homogeneous flowshop signal processing, heterogeneous hierarchical multi-DAG (directed acyclic graph) signal processing in multigroup scanning system ultrasonic phased array with large array are mainly studied. The method also applied to the development of multi-group scanning instrument of large-element ultrasonic phased array.