Abstract: To address the issues of diverse equipment types, non-uniform standards, and non-standard communication protocols in low-voltage distribution networks, an IoT terminal architecture based on the MQTT communication protocol was constructed. This architecture is divided into four layers: the device layer, access layer, business layer, and master station layer. It is adaptable to multiple protocols, achieves software-hardware decoupling, and features plug-and-play functionality. Additionally, several functional models are introduced, including a data acquisition model, a plug-and-play functional model, a data access model, and a log management model. The effectiveness of the IoT terminal architecture and its models was evaluated through an engineering application at a test site in Yibin, Sichuan. The results demonstrate that the proposed IoT terminal architecture and its models have practical engineering application prospects.