The invention relates to a device for utilizing a real triaxial testing machine to realize a rock biaxial tension test. The device comprises a sample bonding component, a stretching component and a supporting component, wherein the sample bonding component comprises an upper slot plate and a lower slot plate; a screw hole is formed at the center of the upper slot plate; the stretching component comprises a first top plate, a first base plate and a connecting rod; the connecting rod is located on slot walls on the two sides of a slot of the first base plate; first through holes are formed on the slot walls on the two sides of the slot of the first base plate; the supporting component comprises a bolt, a second top plate, a second base plate and a brace; a bolt mounting hole is formed at the center of the second top plate; the brace is mounted in each of the first through holes of the stretching component; a second through hole is formed on the second top plate; the connecting rod of the stretching component is mounted in the second through hole; the bolt is mounted on the bolt mounting hole and the screw hole. The device provided by the invention can utilize the real triaxial testing machine to accurately measure the strength and deformation of the rock material under a biaxial tension condition.