ESPs of boiler 2# of Aiyis Power station has, to now, been operated for more than 7 years, but the back corona, dust re-entrainment and rapping difficulty for dust was, due to higher AL2O3 and CaO in ash, higher dust resistivity and very fine particulates as well as large adhere force for fly-ash, often caused. And although a lot of maintenances was to be done, the cleaning efficiency is not satisfied and not to reach the environmental emission standards. For increasing efficiency, after Lanzhou Electric power Equipment Manufacturer was through tapping the existing equipment potential, taking measures suited to local conditions and implementing the revamp program of lengthening and widening ESPs, the emissions, at present, hit the environmental statutes of less than 50mg and also accumulate the rich experiences for congener ESP technology.