In this paper, the current status and latest achievements of ultra-high strength low alloy steels with ultimate tensile strength exceeding 2000Mpa are studied from the aspects of composition, processing, microstructure and mechanical properties, by analyzing the literature. The most conventional heat treatment process for low alloy ultra-high strength steel is quenching and low temperature tempering to obtain lath martensite structure. High carbon chromium bearing steel 100Cr6 is the bearing steel with the largest production volume in the world. If there is no special description for bearing steel, it refers to 100Cr6. Although tempered martensite has high tensile strength, its low toughness can lead to brittle fracture of the material, thus reduce service life.