The invention discloses an intelligent earth wire for connecting an automobile emergency startup power supply with an automobile storage battery. According to the invention, an MCU is adopted as a control chip and combined with a power supply circuit, a temperature detection circuit, a voltage detection circuit, a working state prompting circuit, a load access detection circuit, a load connectionstate identification circuit, a connection control circuit and other peripheral circuits. In this way, an automobile storage battery externally connected with the earth wire can be detected. By meansof the MCU, the connection state of the automobile storage battery can be judged. Meanwhile, when the automobile storage battery is in a positive connection state, the electric connection between a first negative electrode connecting end and a second negative electrode connecting end is connected through a connection control circuit control switch. The automobile emergency startup power supply andthe automobile storage battery are connected in parallel. In this way, the formation of a short circuit at the two ends of the earth wire is avoided. Meanwhile, the occurrence of a safety accident caused by the reverse connection of the automobile storage battery is avoided, so that the product is safer and more reliable.