The results of the BELLE barrel calorimeter prototype test with the tagged photon beam are presented. The prototype consisted of 36 CsI(Tl) counters with the same readout system as the BELLE calorimeter. The measurements were carried out at the VEPP-4 collider with the tagged photon beam provided by the ROKK-1M facility. The energy resolution for photons was measured in the energy range 40-800 MeV. The results are in good agreement with the Monte-Carlo simulation.