We present the covariant BRST quantization of the super-D-string. The non-vanishing supersymmetric U(1) field strength F is essential for the covariant quantization of the super-D-string as well as for its static picture. An SO(2) parameter parametrizes a family of local supersymmetric (kappa symmetric) systems including the super-D-string with F not equal 0 and the Green-Schwarz superstring with F = 0. We suggest that E-1 (the canonical conjugate of the U(1) gauge field) plays the role of the order parameter in the Green-Schwarz formalism: the super-D-string exists for E-1 not equal 0 while the fundamental Green-Schwarz superstring exists only for E-1 = 0. (C) 1998 Elsevier Science B.V.