Abstract: Provided are a microfluidic chip and a usage method therefor, a microfluidic system, and a manufacturing method for a conductive cover plate. The chip includes an extraction assembly and an amplification assembly. The extraction assembly includes a lysis chamber, a first valve chamber, washing chambers, and a second valve chamber that sequentially connect with each other. The amplification assembly includes a chip substrate, a barrier layer, and a conductive cover plate. The barrier layer, the chip substrate, and the conductive cover plate form an elution chamber, a liquid path chamber, and an amplification chamber. A side of the conductive cover plate adjacent to the chip substrate is provided with a cavity having an opening at a bottom, and the elution chamber contains the cavity. The cavity has a thickness of 0.6 mm to 2 mm in a thickness direction of the microfluidic chip.