Abstract: Renewable energy is a critical energy foundation for promoting deep decarbonization of the steel industry,and its supply stability and coupling adaptability directly determine the decarbonization efficiency. This paper systematically reviews the application history, major difficulties,and developing trends of solar energy, biomass energy, and wind energy in the steel industry. It shows that photovoltaic power generation has achieved large-scale application in distributed settings within the steel industry, however, the fundamental contradiction between its intermittency and the continuity of smelting processes has yet to be resolved.As a substitute for coke, biochar as a reducing agent faces several metallurgical bottlenecks, including high reactivity, alkali metal enrichment, and insufficient mechanical strength, which significantly limit its industrial injection ratio. Wind power can replace part of the energy demand in coastal or northwestern steel plants through self-developed wind farms, but its deployment is constrained by regional resource availability and limited construction space.Based on these findings, two core contradictions in coupling renewable energy with steelmaking processes are identified in this paper. First, the spatiotemporal mismatch between the intermittent nature of renewable energy supply and the continuous requirements of smelting, second, the conflict between the regionally differentiated characteristics of renewable resources and the stringent demands of metallurgical raw material quality. Looking forward, relying on a single energy source as a substitute cannot fundamentally solve the problem. The deep integration of multi-energy complementary systems with the hydrogen-based direct reduction short process represents the leading pathway toward establishing a zero-carbon closed loop of green electricity, green hydrogen, and green steel. Accordingly, this paper recommends differentiated, region-specific strategies, coastal steel plants should develop offshore wind power and hydrogen metallurgy, inland resource-rich areas should pursue wind-solar power generation coupled with energy storage, and biomass-rich regions should advance biochar injection into blast furnaces.