Abstract: Based on the Multi-Voltage Threshold method, the All-Digital PET technology (with " All-Digital" and "accurate sampling" as its two essential features) allows for hardware and software decoupling and "LEGO" construction of the system, overcoming the limitations of the conventional PET system architecture and providing more innovative application possibilities. In this study, we described the recent research progress on application-specific All-Digital PET systems and their related applications and advantages in proton therapy monitoring, clinical and basic research in brain science, and plant metabolism research. Moreover, in response to higher-level requirements for PET imaging systems in cutting-edge applications, we further discussed the development trend of the All-Digital PET technology.