Abstract: Ordinary alkali-activated slag composites（AASC） were formed by slurry casting and had many large internal pores and visible cracks, so they led to problems such as high brittleness, low strength and easy fracture.To overcome these drawbacks, the study prepared alkali-activated slag composites using slag as the matrix, sodium silicate as the alkali activator, and copper fibers as the reinforcement by hot-press moulding.The effect of copper fibers on the mechanical properties of hot-press moulding alkali activated slag composites（HP-AASC） were tested using XRD,SEM,compression, flexural strength, impact toughness, porosity, and other methods.The results shown that the mechanical properties of the hot-press moulding samples were better than those of the casting moulding samples.The sample was more dense when slag powder reacts with the alkali activator during alkali activator and hot-press.The best mechanical properties were achieved when the slag∶alkali activator ratio was 3∶1 and the copper fiber content was 7%.The samples had compressive and bending strength of 149.72 MPa, 27.07 MPa, and an impact strength of 0.44 J/cm².They had less than 5% porosity.The copper fibers on the composites made them stronger and more durable.