The results of test study on mixedly burning gangue in circulating fluidized bed(CFB) boiler have been presented.It has been suggested to define the ratio of mixed gangue by using the ash content of furnace-incoming fuel as received basis

and to calculate the practical amount of mixed gangue

and combining with concrete example

the problems needing to pay attention for reasonably determining the ratio of mixed gangue and for operation of CFB boiler under condition of mixedly burning gangue have been analysed

the results have certain reference value for some power plants adopting CFB boilers to reasonably use gangue for power generation based on their respective actual situation.