The invention discloses an automobile wire harness plug-in unit convenient to overhaul. The automobile wire harness plug-in unit comprises a plug-in unit body, an outer shell, a terminal and an elastic piece mechanism. The plug-in unit body comprises a front end and a rear end, the rear end is inserted into the outer shell, and a containing cavity is formed between the rear end and the outer shell; an opening is formed in the top of the outer shell, and a U-shaped guiding frame is arranged at the opening; the elastic piece mechanism is fixed into the U-shaped guiding frame through a connecting rod, and a hook-shaped part is arranged at the bottom of the end, close to the front end, of the elastic piece mechanism; the plug-in unit body is internally provided with a plurality of terminal installation holes penetrating through the front end and the rear end, and a first groove is formed in the top of the front end; an overturning cover is arranged in the first groove, and the bottom of the first groove communicates with all the terminal installation holes; and the bottom of the overturning cover is provided with first limiting protrusions arranged opposite to all the terminal installation holes in a one-to-one mode, and the tops of the terminals are provided with limiting baffles matched with the first limiting protrusions. According to the automobile wire harness plug-in unit, an open-type structure is adopted, and the automobile wire harness plug-in unit has the advantages that troubleshooting is convenient, and terminal replacing is quick.