As key participants in the national carbon market, the rational use of trading strategies by thermal power enterprises is conducive to reducing compliance costs and enhancing the value of carbon assets. The microstructure of the carbon market is first characterized, and trading scenarios are classified into allowance surplus, balance, and deficit based on allowance allocation relative to compliance requirements. Under each scenario, optimal strategy choices under strong-trend and weak-trend market states are examined, showing that trend-following strategies perform best in strong-trend states, while mean-reversion strategies dominate in weak-trend states. Further results indicate that a combined strategy integrating both approaches outperforms single strategies, increasing returns by 3.0%~5.4% in surplus scenarios and by 17%~33% in balanced scenarios, while reducing costs by 0.1%~6.6% in deficit scenarios. A differentiated trading strategy framework work based on market structure and market trends is thus constructed to guide thermal power enterprises in more effective participation in the national carbon market.