  The Poincar\'e invariance of GR is usually interpreted as Lorentz invariance
plus diffeomorphism invariance. In this paper, by introducing the local
inertial coordinates (LIC), it is shown that a theory with Lorentz and
diffeomorphism invariance is not necessarily Poincar\'e invariant. Actually,
the energy-momentum conservation is violated there. On the other hand, with the
help of the LIC, the Poincar\'e invariance is reinterpreted as an internal
symmetry. In this formalism, the conservation law is derived, which has not
been sufficiently explored before.
