  We show the XXX model has the N = 2 dynamical supersymmetry. Using the
supercharges defined by the Jordan-Wigner fermions, it was found that the
anti-commutation relation of the supercharges gives the Hamiltonian of the XXX
model with magnetic field. In order to compare the length-change supercharges
with the conventional ones, we interpreted their actions in the spinon basis.
In the last part of this paper, we propose the application of the dynamical
supersymmetry to the models with magnetic impurities through the Bethe-ansatz
analysis.
