[en] Electron cyclotron emission imaging (ECEI) diagnostic system with 384 channels was installed on EAST tokamak. Since EAST was equipped with 4MW ICRF system, 4MW LHCD system and NBI system, the ECEI diagnostic system on EAST was heavily interfered, especially by the lower hybrid wave. The optimization of the electromagnetic shielding is presented, which help to reduce the interference to 40dB. Appropriate copper mesh shield and the correct ground connection are the key solutions. The comparisons of the ECEI raw signals before and after the optimization clearly show that the shielding performance is greatly improved. (authors)