Abstract: The utility model refers to an automobile start-up adapter, wherein it comprises a shell and a circuit board provided inside the shell. The shell is provided with an input terminal for electrically connecting with an output terminal of a lithium battery of a power tool and an output terminal for electrically connecting with a clamp. The input terminal and the output terminal are communicated through a circuit board, and a voltage identification circuit and a voltage conversion circuit are provided on the circuit board. The automobile start-up adapter of the utility model can use the lithium battery of the hand-held electric tool to supply power for the emergency start-up of the automobile.