Background. Auxiliary liver transplantation is accepted as an effective manner to expand the liver donor pool. A difficult surgical technical challenge of the procedure is hepatic vein reconstruction of the graft. Methods. To resolve this problem, complex techniques are used to perform an innovative outflow tract reconstruction in the world's first cross-auxiliary double-domino donor liver transplantation with two whole liver grafts. The inferior vena cava sparing hepatectomy technique was applied at harvest in the two domino liver donors. For each donor, the three major hepatic veins (right, middle, and left) were joined together to create one single orifice, but there was no sufficient tissue to perform a direct anastomosis. Results. The hepatic vein was reconstructed with the use of a longitudinally opened iliac vein graft from a cadaveric donor to prolong the outflow tract for the piggyback suturing. Conclusions. This new technique might provide an innovative surgical approach for reconstructing the complex outflow tract of domino transplantation.