To investigate the electrothermal properties of nickel-plated carbon fiber (Ni-CF) cement-based materials, the Ni-CF was mixed into cement to prepare thermally conductive cement-based composites. The effects of water-cement ratio (W/C), fiber content and length on the heating law of cement paste specimens were studied, and the variation law of the maximum temperature rise and the difference of the electrothermal conversion rate were analyzed. The results show that when the content of nickel-plated carbon fiber increases from 0.3% to 0.6%, the maximum temperature rise of the specimens increase first and then decrease, among them, the sample with 0.4% (mass fraction) Ni-CF content has the best heating effect. With the increase of Ni-CF length from 4 mm to 8 mm, the maximum temperature rise of cement paste specimen decreases gradually. The increase of the water-cement ratio leads to the maximum temperature rise of the nickel-plated carbon fiber cement paste. Under the same intensity of the current, the electrothermal conversion rate of Ni-CF cement specimens reach 71.98%, which is twice as high as that of carbon fiber (CF) cement specimens under the same mix ratio.