  We focus on a nonlinear supersymmetry (NL SUSY) in curved spacetime
introduced in the superon-graviton model (SGM) towards a SUSY composite unified
model based on SO(10) super-Poincar\'e symmetry, and we consider for $N = 1$
SUSY a systematic procedure to linearize the NL SUSY. By introducing modified
superspace translations of superspace coordinates and their specific coordinate
transformations both depending on a Nambu-Goldstone fermion, we show a
homogeneous transformation's law of superfields which is important in the
relation between linear (L) and NL SUSY. Furthermore, as a preliminary to find
a L supermultiplet which is equivalent to the $N = 1$ NL SUSY SGM multiplet, we
discuss on the realization of the modified superspace translations in the
construction of a supergravity-like multiplet in the superspace formalism. In
particular, we find constraints on a torsion and a Lorentz transformation
parameter in the superspace formalism to realize the modified
supertranslations.
