Abstract: The electrical resistance of cement paste with and without carbon fibers during hydration was measured and the relationship between hydration and compressive strength and electrical resistance was investigated. The effect of adding an early-strengthening agent or heating was also studied. Results show that the electrical resistance of the cement paste fluctuates sharply during measurement because of strong polarization. The fluctuation of electrical resistance of the carbon fiber reinforced cement paste (CFRCP) disappears when more than mass fraction 0.30% of carbon fibers is added, and the electrical resistance shows a linear relation to the extent of hydration when the carbon fiber mass fraction is 0.35%. The same results are observed for CFRCP treated by the early-strengthening agent or heat curing. Therefore, it is feasible to monitoring the hydration of cement-based materials by testing its electrical resistance.