Red sandstone has the characteristic of water softening. By comparing with limestone aggregate, the hardness and softening resistance performance of coarse and fine aggregate of red sandstone were studied. Then the influence law of red sandstone aggregate on the strength and softening resistance performance of cement stabilized base were studied. The mineral composition and microstructure of red sandstone and limestone aggregate before and after immersion were compared by boundary moisture content measurement, XRD and SEM examination. The results show that the weight and hardness of red sandstone aggregate decrease after immersion, and the softening resistance performance becomes worse. The strength and softening coefficient of cement stabilized red sandstone base are lower than those of cement stabilized limestone base, but the decreasing degree of strength and softening coefficient of cement stabilized red sandstone coarse aggregate base is less than those of cement stabilized red sandstone fine aggregate base. The main reason for the decrease of strength and softening coefficient of cement stabilized red sandstone base is that clay minerals in red sandstone aggregate are disintegrated and expanded in water. This study provides theoretical reference for the composition design and application of red sandstone in pavement base.