  In this article, I obtain the Einstein and M{\o}ller energy complex in PG
coordinates. According to the difference of energy within radius $r$ between
Einstein and M{\o}ller prescription, I could present the difference of energy
within radius $r$ like the fomula of Legendre transformation and propose that
the M{\o}ller and Einstein energy complex play the role of internal energy and
Helmholtz energy in thermodynamics.
