  The beam energy measurement system for the VEPP-2000 electron-positron
collider is described. The method of Compton backscattering of $CO$ laser
photons on the electron beam is used. The relative systematic uncertainty of
the beam energy determination is estimated as 6\cdot10^{-5}. It was obtained
through comparison of the results of the beam energy measurements using the
Compton backscattering and resonance depolarization methods.
