A magnetic attraction arc-mouth clamp, belonging to the technical field of a hand tool, is formed by a left half clamp 1 and a right half clamp 7 that are hinged via a clamp shaft 3. A left clamp handle 2 and a right clamp head 4 are combined into a whole body to form the left half clamp 1. A right clamp handle 8 and a left clamp head 9 are combined into a whole body to form the right half clamp 7. Each of the right clamp head 4 and the left clamp head 9 is equipped with an arc jaw 6. A magnetic bar 5 is disposed close to each arc jaw 6 on each of the right clamp head 4 and the left clamp head 9. The arc jaws 6 can reliably clamp screws with nail heads of various kinds and matched pads passing through the screws are attracted by magnetic attraction, so the screws can be mounted and dismounted in a deep recess in a reliable and highly efficient manner. The magnetic attraction arc-mouth clamp is used for accurately and reliably putting screws in a deep recess and for removing the screws together with pads.