C50 grade high-performance (HPC) fly ash concrete is used in the cable support tower of Jiujiang Yangtze River highway bridge and the appearance quality is required to meet the standard of fair-faced concrete.Aiming at the engineering practice and actual service environment of the bridge site, we put forward the appearance quality control index and durability design requirements for the cable support tower HPC fair-faced concrete structure, and study the alkali reaction activity of aggregates and the effects of fly ash content on resistances of the cable support tower concretes to carbonation, acid rain, permeability and freezing-thawing through experiment. The results show that the sand and crushed stone used in the engineering construction has no alkali activity, and the comprehensive durability of the cable support tower concrete is improved by 22.5% fly ash as the substitution of portland cement and meets the design index requirements.