The invention relates to the technical field of weak force test, and specifically relate to a suspension calibration device and a calibration method for weak force test. The calibration device includes a mounting frame, a stand, a micro thruster, a micrometer, a first calibration component, and a second calibration component. The calibration device of the present invention adopts the first calibration component, and hangs a calibration ball with known weight below a micro-nano translation stand. The calibration ball abuts against a calibration end surface of the stand under the driving of themicro-nano translation stand, and a component force of a tensile force of a suspension wire in a horizontal direction is a calibration input, so as to simplify structure of the device while ensuring test accuracy. The calibration device of the invention is used for calibration with simple operation.