Amorphous carbonas one of disordered carbon materials usually exhibits different mechanical, electrical, optical and thermal properties from crystalline carbon materials. Exploring high-performance amorphous carbon materials is always a research hotspot. In this paper, a high-strength amorphous carbon composed of onion-like structural elements was reported. This kind of amorphous carbon was obtained via treating carbon black at high temperature and high pressure (i.e., 1700–2000 ℃ and 6 GPa), which shows excellent mechanical properties. The nano indentation hardness, indentation elastic recovery, uniaxial compressive and flexural strength of the sample with best performance are 5.1 GPa, 80.1%, 956.4 MPa and 216.0 MPa, respectively. The compressive and flexural strengths of the amorphous carbon are 5.6 times and 2.8 times greater than those of Toyo Tanso ISO-68 graphite, respectively. This kind of amorphous carbon also has a good conductivity, and its room-temperature resistivity can be as low as 75.7μΩ·m. This high-strength conductive amorphous carbon can be widely used as electrode and mold materials.