The invention discloses a zero-bending-moment shield tunnel. The cross section of the shield tunnel is in an egg shape with the upper portion smaller than the lower portion. The center horizontal diameter of the axis of the cross section of the shield tunnel is located in the center of the vertical diameter, the maximal horizontal diameter of the axis of the cross section of the shield tunnel is located below the center horizontal diameter, the interval between the maximal horizontal diameter and the center horizontal diameter is the eccentric distance delta, and the vertical diameter is larger than the maximal horizontal diameter. The zero-bending-moment shield tunnel has the advantages that compared with a traditional shield tunnel, the bending torque of the shield tunnel is reduced to the maximum under the condition of not increasing the construction cost basically, deformation of the cross section of the shield tunnel and expanding deformation of a pipe piece longitudinal seam joint are reduced, and therefore breakage and water seepage of the pipe piece longitudinal seam joint are avoided. In addition, compared with an existing shield tunnel pipe piece, the use quantity of rebars of the pipe piece can be reduced.