Abstract: The gas-water-gas heat exchanging system (WGGH) operation situation is analyzed through field tests and study from the aspects of gas temperature drop, system resistance, dust removing efficiency and SO₃ removing efficiency. The results show that the chimney smoke temperature can be raised through WGGH and the white smoke plume can be eliminated. Meanwhile, the removal of dust and SO₃ has obvious effect. The main problems of WGGH in operation are analyzed and the corresponding optimization and improving measures are proposed to provide important data support and theoretical basis for normal WGGH operation.