Abstract: Utilizing the Multi-Voltage Threshold method, All-Digital PET technology, characterized by "All-Digital" and "accurate sampling," facilitates hardware and software decoupling and modular "LEGO-like" system construction. This innovation addresses the limitations of traditional PET system architectures, enabling a broader range of innovative applications. This paper reviews recent advancements in application-specific All-Digital PET systems, highlighting their applications and advantages in proton therapy monitoring, clinical and basic brain science research, and plant metabolism studies. Furthermore, we explore the development trends of All-Digital PET technology to meet the increasing demands of PET imaging applications.