The utility model discloses a lithium battery diaphragm area resistance testing device capable of overcoming the large error of the prior art. The lithium battery diaphragm area resistance testing device comprises a pedestal, a transmission assembly, a connecting plate, an upper electrode assembly, and a lower electrode assembly. The upper electrode assembly is fixedly connected with the connecting plate, and the lower electrode assembly is fixedly disposed on the pedestal. The transmission assembly is fixedly disposed on the pedestal, and is used to drive the upper electrode assembly to move upwards and downwards by the connecting plate. The upper electrode assembly comprises an upper plate electrode, and the lower electrode assembly comprises a lower insulation clamping sleeve and a lower plate electrode. The lower insulation clamping sleeve is provided with a lower installation groove, in which is disposed the lower plate electrode opposite to the upper plate electrode. A liquid guiding groove can be formed between the side wall of the lower plate electrode and the inner wall of the lower insulation clamping sleeve. The thickness of the lower plate electrode is equal to or greater than the thickness of the lower installation groove. The upper plate electrode and the lower plate electrode are electrically connected with the electrochemical working station. The error of the diaphragm area resistance test is small by using the lithium battery diaphragm area resistance testing device.