Three-phase four-wire rail type smart meter, can realize two-way communication through RS485 for reading and setting power data and parameters. The built-in high-quality magnetic holding relay can carry out user-side load management, and the backlight can be lit through the button to facilitate viewing data at night. The metering method can be set to meet the requirements of bidirectional measurement. The meter has multi-functions and compact structure, and is suitable for various application scenarios such as residential households, industrial fields, new energy charging piles, and renewable energy power generation.