As the global energy structure transforms and the “dual-carbon” goals are set， green hydrogen is gaining importance as a clean energy source in the petroleum refining industry. This study comprehensively assesses the technical and economic viability of producing green hydrogen， methanol， and ammonia using offshore wind power. By calculating the costs of hydrogen production， methanol synthesis， and ammonia synthesis under varying electricity costs， the study analyzes how electricity prices affect the economic viability of green hydrogen and its derivatives. The results indicate that when the electricity cost is 0.35 yuan per unit， the current alkaline electrolysis hydrogen production technology yields a hydrogen cost of 24.66 yuan/kg in the scenario of offshore wind power and onshore hydrogen production， with methanol and ammonia production costs of 5457.55 yuan/ton and 4999.43 yuan/ton， respectively. The study emphasizes that electricity cost is the key factor influencing economic viability. Reducing renewable energy electricity costs and enhancing electrolysis efficiency are crucial for boosting the competitiveness of green hydrogen and its derivatives. Finally， the article proposes suggestions for the coordinated development of policies， technologies， and industries to promote the industrialization of green hydrogen and its derivatives.