Controlled rolling followed by accelerating cooling was adopted during industrial processing of a low-C V-N microalloyed steel. Furthermore, the effect of finish cooling temperature on the microstructure and mechanical properties was studied. The microstructure consisted of polygonal ferrite and coarse pearlite at finish cooling temperature of 660°C, while fine pearlite was obtained instead of coarse pearlite at finish cooling temperature of 630°C. With further decrease in finish cooling temperature to 570°C, the microstructure comprised of fine polygonal ferrite, acicular ferrite, and a small amount of fine pearlite, such that high yield strength of 625MPa and excellent impact toughness of 149J at −60°C was obtained. Acicular ferrite characterized by fine non-parallel ferrite platelets and high degree of misorientation played a determining role in enhancing strength and toughness.