There is no appropriate method or uniform standard for evaluating the pozzolanicity of CFB sulphur-fixed coal ashes,leading to difficulty in use of it as building material,because CFB sulphur-fixed coal ash has higher content of f-CaO and SO_3 than that of ordinary ash.In this paper the appropriate evaluating methods are developed through theoretical analysis and experiments with reference to the National standards GB2847 for the pozzolanic materials and GB12957-91for the testing method of the activity of the industrial wastes,the compressive strength ratio is suggested by determination of 28 day compressive strength ratio of ground CFB sulphur-fixed coal ashes-clinker to ground clinker.It is shown that this evaluating method gives the results consistent with those from other methods.