The signal communication module based on serial communication interface communication and self-power supply is composed of a plug, a power-taking circuit, a hierarchical power supply circuit, an MCU circuit, a communication circuit and a housing. The power-taking circuit includes a limiting input cable, a polarity conversion circuit, a voltage-stabilizing output circuit and an input protection circuit. The power-taking circuit obtains power from the electrical signal used for communication on the communication signal line (such as TxD) of the serial port, without affecting the serial port. In the case of communication, through current limiting, voltage limiting, frequency limiting and related processing, signal communication and self-power collection are completed. The serial port communication module also includes sniffing logic, which can automatically identify the brand and model of the container when the input terminal is connected to the refrigerated container, and pass the information through the communication circuit to complete the communication with the external logic. This module is used in container ships, land container transport vehicles, container terminals, and container yards as the core equipment for remote monitoring and control of containers.