The invention discloses an anastomosis cannula for establishing a rat inferior vena cava replacement model. The anastomosis cannula comprises a first silica gel hose, a second silica gel hose, a wrapping outer pipe, a spiral soft wire, a guide positioning wire, a guide hole, a fixed strip, a pressure spring, a movable strip, a fixed ring, a fixed strip frame, a connecting block, a threaded rod, a knob disc, a connecting sleeve, a connecting soft rope, a movable through groove, an inclined rod, a pressing strip, a mounting screw, a soft ring, a positioning sleeve, a pull rope, a first bearing, a lantern ring, a concave hole, a second bearing, a spiral spring and a bolt. The nut comprises a nut base, a strip-shaped cavity, a silica gel protrusion, a deformation inner cavity and a hinge shaft. The anastomosis cannula has the advantages that the anastomosis cannula serves as a limiting and supporting assembly of the donor vein, the donor vein section is turned outwards and reversely folded to the cannula, the supporting and fixing effects are achieved, blood vessels at the two broken ends of a donor and a receptor can be well combined, the operation time is greatly shortened, postoperative bleeding and anastomotic stoma stenosis are reduced, and the operation success rate and the model stability are improved.