The electromagnetic calorimeter is designed to give the most precise and important measurement of particles' energies. It can measure energies between a few tens of MeV up to 100 GeV. It measures the energies and positions of electrons, positrons and photons, and helps to discriminate between electrons and hadrons. ECAL is divided into a barrel region and two endcap regions and gives a coverage of 98% of the solid angle. Each region consists of a presampler in front of a lead-glass calorimeter.