To improve the real-time damage monitoring effect of building structures in cold regions, the durability and piezoresistivity of self-sensing cement mortar prepared by using chopped carbon fiber and iron tailings as conductive materials under the sulfate freeze-thaw cycles were studied. Based on the mass loss, relative dynamic elastic modulus and compressive strength loss, the change law of durability performance was studied, the correlation between fractional change in resistivity and compressive stress was used to reflect the development law of piezoresistivity under the sulfate freeze-thaw cycles and the conduction mechanism was explained, the average stress sensitivity coefficient was used to evaluate the stability of piezoresistivity under the sulfate freeze-thaw cycles. The results show that cement mortar combined with 0.4% volume of carbon fiber and 30% (mass fraction) replacement rate of iron tailings reach a better level of durability and piezoresistivity. The fractional change in resistivity-compressive stress shows a first-order exponential decay relationship due to the holes and cracks caused by sulfate freeze-thaw cycles. The Plane model can be used to reflect the good correlation among the attenuation degree of average stress sensitivity coefficient and the number of freeze-thaw cycles and the replacement rate of iron tailings.