EU-China Comprehensive Agreement on Investment (CAI) and the Comprehensive and Progressive Trans-Pacific Partnership Agreement (CPTPP) contain relatively high standards of environmental protection clauses. The paper combines the texts of CAI and CPTPP environmental rules, and comprehensively compares the content of the two in terms of guiding concepts, cooperation mechanisms and dispute settlement mechanisms. On the basis of analyzing the influencing factors of environmental protection clauses, it proposes possible solutions to the challenges of construction of environmental protection clauses, improvement of cooperation mechanism and optimization of implementation mechanism that China will face in the CPTPP and future economic and trade negotiations.