Abstract: The aligned carbon fiber reinforced cement mortar was prepared by magnetic field induced orientation technology. The carbon fiber orientations, compression strengths and splitting tensile strengths of cement mortars with different water-cement ratios, ages and fiber contents were measured. The effects of carbon fiber content and orientation on the mechanical properties of prepared cement mortars were studied. The results show that the water-cement ratio and fiber content have a significant effect on the orientation of carbon fiber. Besides, compared with the ordinary carbon fiber reinforced cement mortar, the aligned carbon fiber reinforced cement mortar has a significant increase in the splitting tensile strength, while exhibits no obvious change in the compressive strength. With the same water-cement ratio, the fiber orientation and fiber content are the main factors affecting the splitting tensile strength of aligned carbon fiber reinforced cement mortar. Especially, the optimum content of carbon fiber in the aligned carbon fiber reinforced cement is 0.50% of the cement mass, which has the highest increasing ratio of splitting tensile strength.