Abstract: A capacitive sensing car-door pre-opening warning device based on a flexible printed circuit in the present application comprises an inside door handle trim panel, an inside door handle subassembly, a flexible printed circuit, a capacitive sensing element, a capacitive-sensing processing circuit, a warning unit and a control unit wherein: the inside door handle trim panel is designed to have a through hole as well as an accommodating space; the inside door handle subassembly has a portion penetrating the through hole and linking the car door linkage and another portion covered in the accommodating space which is sensed by the capacitive sensing element; the capacitive-sensing processing circuit generates a sensing capacitance after processing for development of a warning instruction from the control unit and activation of a warning mode configured in the control unit according to the warning instruction.