Pre-tightening clamp

The utility model belongs to the technical field of battery testing tools, and particularly relates to a pre-tightening clamp which comprises a first clamping plate, a second clamping plate, a plurality of fasteners, a plurality of tightening pieces and a base provided with a plurality of fixing holes, and the bottom wall of each fixing hole is provided with a polygon prism; the first clamping plate is provided with a plurality of first through holes, the second clamping plate is provided with a plurality of second through holes, and the fastener is provided with a polygon prism matched with the polygon groove. One end of the fastener sequentially penetrates through the first through hole and the second through hole and then is inserted into the fixing hole, and the polygon prism is inserted into the polygon groove. The tightening piece is connected to the fastening piece in a sleeving mode and used for adjusting the pre-tightening force of the first clamping plate and the second clamping plate on the to-be-c