It accomplished frequency regulating modification of secondary air fan motor of CFB boiler in Yunnan datang honghe power generation Co.Ltd in 2010,Inverter’s type is HARSVERT-A06/270,which is the product of HARSVERT company, Mode of running is one running, another stand-by, mode of cooling is water air cooled. After modification, both regulating quality and effect of energy conservation are excellent, According to the frequency regulating modification of secondary air fan motor of CFB boiler in honghe power generation Co.,Ltd, it provides successful reference for modification of energy conservation in large CFB boiler units.