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The method of discrete symmetries and conserved quantities is applied to field theory.The discrete variational integrators in field theory are investigated by means of the difference discrete variational principle in which the difference is regarded as an entire geometric object.The Lie group of the discrete infmitesirnal transformations is used to define the discrete Lie symmetries in field theory.The determining equations of the discrete Lie symmetry are derived from the variational integrators and the Lie group transformations.The discrete counterparts of the Noether theorem is obtained.