Adjustable prestress bridge support

The utility model relates to the field of bridge supports, and discloses an adjustable prestress bridge support which comprises a support body, two first sliding grooves are formed in the support body, second sliding grooves are formed in the positions, at the tops of the two first sliding grooves, of the support body, and third sliding grooves are formed in the positions, at the tops of the two second sliding grooves, of the support body. The first sliding groove communicates with the second sliding groove, the second sliding groove communicates with the third sliding groove, a lead screw is arranged in the support body and sleeved with a first threaded sleeve, two first sliding blocks are fixed to the outer wall of the first threaded sleeve, the first sliding blocks are matched with the first sliding groove, the second sliding groove and the third sliding groove, and the top end of the lead screw is sleeved with a second threaded sleeve. And two second sliding blocks are fixed to the outer wall of the secon