Abstract: The adaptability of low-calcium fly ash, high-calcium fly ash, ground fly ash, desulfurized fly ash, denitrified fly ash with naphthalene and polycarboxylic superplasticizer was systematic researched by comparing cement paste fluidity method. The differences of adaptability between fly ash and admixtures are analyzed through SEM, adsorption and Zeta potential experiments. The results show that the fly ash has high selectivity and adaptability to different admixtures obviously. The amount of additive is positively correlated to water demand ratio, but not existed a proportional relationship. Compared with low-calcium fly ash, denitrified fly ash can adapt additives well by fine water-reducing, slump-remaining characteristic or even better in these aspects. Ground fly ash and desulfurized fly ash have bad adaptability to additives because they have a negative effect on initial fluidity and fluidity retaining. High-calcium fly ash also can’t adapt additives well because it makes the slump loss aggravated. The microstructure and unburned carbon content determined the adaptability of different fly ash and admixtures through the effect on adsorption and Zeta potential properties. High-calcium fly ash and denitrified fly ash can adapt additives well because they have the similar micro morphology and adsorption performance to ordinary fly ash, while ground fly ash and desulfurized fly ash have bad adaptability to additives for its rough surface and high carbon content increased additives serious loss.