Abstract: Graphene (G) could effectively improve the mechanical and electrical properties of cementitious materials, but it was too expensive and poor dispersion. To reduce the cost and investigate carbon nanomaterials with good electrical conductivity and dispersion, nitrogen-doped thin-layer carbon sheets (NGCNs) were successfully prepared by the one-step pyrolysis method in this paper to study their effects on the mechanical and electrical properties of cement mortar. When the dosage of NGCNs is 0.07wt%, the 7 d and 28 d flexural and compressive strengths were increased by 15.9%, 19.8%, 14.4%, and 17.9%, respectively, compared to the mortar specimens in the undoped graphitized carbon sheets (GCNs) group. At a dosage of 0.5wt% of NGCNs, the modified mortar specimens reached a heating rate of 12.7℃/min. This discovery has led to cementitious materials showing great potential for applications in smart buildings, snow and ice melting on roads, and electrical energy storage.