Abstract: Renewable Energy Certificate and Emission Trading Scheme, as core market-oriented tools to promote low-carbon transformation, have important practical significance in enhancing effectiveness of national climate governance. By systematic analysis of current legal and policy status of the collaboration between the two systems, it is found that the Energy Law and local pilot programs provide a preliminary legal framework for institutional collaboration. However, issues such as insufficient legal synergy at the central level, fragmented rules in local pilot programs, repeated calculation of environmental interests, and blurred market boundaries, severely constrain collaborative efficiency of two markets. Therefore, China should start from improving legal system for coordination of two markets, establishing a mutual recognition mechanism for environmental interests, unifying market operation and regulatory rules, and improving the international carbon tariff response system, which is conductive to stimulate market vitality under "dual carbon" goals.