The invention discloses a lithium ion battery fire early warning device based on a single chip microcomputer. The device mainly comprises a fire signal monitoring system and a communication early warning system. The fire signal monitoring system mainly comprises an infrared temperature sensor, a carbon monoxide gas sensor, a smoke gas sensor and the like. The communication early warning system mainly comprises an Arduino single chip circuit board, a liquid crystal display (LCD), a warning buzzer, a warning indicator and the like. The fire signal monitoring system monitors the working state ofa target lithium ion battery in real time, and transmits a signal to the control center of the single chip microcomputer. After the single chip microcomputer makes the corresponding judgment, the actual working state of the target lithium ion battery is acquired to determine whether a warning sound and light signal is issued and whether follow-up firefighting linkage measures are taken. The fire signal monitoring system and the communication early warning system cooperate with each other and work together to detect a danger in the early stage of the thermal runaway of the lithium ion battery and take countermeasures.