In this paper, super-fine high-speed steel powders with low oxygen content were prepared by electroslag remelting and atomizing technology, and high-performance PM high-speed steels were fabricated by non-capsule hot isostatic pressing technique. The effects of different particle size and oxygen content of high-speed steel powders on sintering characteristics, microstructure and performance were studied. The results showed that due to the high-speed steel powder with the particle size of less than 12 μm and lower than 100 ppm oxygen, the as-sintered microstructure was uniform and carbides were fine. After heat treatment, the bend strength, impact toughness and hardness reached 4200 MPa, 22 J, and 65 HRC, respectively.