Abstract: 10Ni3MoVD steel ingot was forged to steel plate at a forging ratio greater than 3.5, and then treated by quenching-tempering heat treatment. The microstructure, tensile properties and cryogenic toughness of the steel were studied. The results show that the microstructure of the tested steel was mainly composed of tempered sorbite and bainite. The grain size at differernt thickness positions was not lower than grade 9.5. The tensile properties of the tested steel met the requirements of the NB/T 47009-2017 standard. At -50℃, the tested steel had an excellent impact toughness; the total impact obsorbed energy was not lower than 176 J, the percentage of crystallinity was lower than 20%, the lateral expansion was greater than 2.25 mm and the nil-ductility transition temperatures of the surface layer and at 1/4 thickness position were -75, -65℃, respectively.