Explain the definition of foreign direct investment and the need for protection (its shortcomings and advantages), and analyze various protection methods for foreign direct investment, such as ICSID, bilateral investment treaties, multilateral investment treaties, etc. Use the case or treaty provisions to analyze the protection details. Then it analyzes the protection mechanism of foreign direct investment in infrastructure investment and commodity market investment. In terms of infrastructure investment, take China's regulatory protection mechanism as an example for analysis. Conduct anti-dumping and anti-subsidy analysis on the commodity market investment.