Based on the high concentration saline-alkali environment in northwest China， the mechanical properties and damage evolution of high performance concrete （HPC） with large amount of mineral admixtures and fine aggregate with potential alkali activity exposed in Na⁺-Cl^--SO42- brine were studied. The results show that the relative dynamic elastic modulus and the corrosion resistance coefficient of HPC are greater than 90% and 1， respectively， and the linear expansion ratio of HPC is less than 0.12%. The high equivalent alkali content aggravates the alkali-silica reaction （ASR） in HPC to some extent. Air entraining can improve the brine attack resistance of HPC and reduce the expansion by ASR. HPC of C50 prepared by large amount of mineral admixtures and fine aggregate with potential alkali activity has excellent long-term durability in Na⁺-Cl^--SO42- brine.