Abstract: Using oxide metallurgy technology to develop high heat input welding steel is an important guarantee for the development of marine engineering equipment and high-tech ships in China’s marine strategy. The theory of microalloying based on oxide metallurgy is the basis of the breakthrough and development of oxide metallurgy technology, and it is an urgent subject to be deeply and systematically studied. Herein, the development of oxide metallurgy technology at home and abroad was introduced, and then the progress of microalloying theory based on oxide metallurgy was expounded. Meanwhile, the coordination and interaction of various microalloying elements, and the influence of inclusions and second-phase particles precipitation and evolution on the microstructure transformation and steel properties were analyzed. The influence mechanism of the process of melting, solidification, hot working, and welding on the microstructure evolution, grain refinement, and preferential precipitation of intragranular ferrite was elaborated. The theory of microalloying based on oxide metallurgy is put forward, and its similarities and differences with traditional microalloying are compared; further research work on the theory of microalloying based on oxide metallurgy is prospected.