To slow down climate warming and achieve sustainable development, the Paris Agreement attempts to establish cooperative approaches (Article 6.2 in the Paris Agreement) and a sustainable development mechanism (Article 6.4 in the Paris Agreement) for carbon trading. However, deficiencies in implementation exist due to a lack of systematic execution regulations and an integrated management system. To strengthen the effectiveness of the two carbon trading mechanisms for reducing carbon emission, this paper aims to propose an implementation framework of cooperative approaches and a sustainable development mechanism. Based on the international regime theory in global climate change and the nine elements of the market mechanism, the paper makes use of comparative analysis to discuss the type of mechanism, coverage of the system, operational framework, governance framework, and implementation framework of cooperative approaches and a sustainable development mechanism. The main results and conclusions are as follows: (1) Cooperative approaches are considered as project-based and quota-/credit-based carbon market mechanisms. Under cooperative approaches, trading units should be authorized at the international-regional and sub-regional levels. CO2, CH4, N2O, HFCs, PFCs, SF6, and NF3 are the seven types of greenhouse gases that could be traded through cooperative approaches, and they shall be accounted by the unit of CO2-eq. (2) The sustainable development mechanism is considered as an industry-based and credit-based carbon market framework. Under the sustainable development mechanism, trading units should be authorized at the international level. CO2, CH4, N2O, and PFCs can work in the sustainable development mechanism as subject matters. The unit of gases shall be CO2-eq as well. (3) The implementation framework of cooperative approaches ought to follow three stages: project preparation, project submission, and auditing, as well as internationally transferred mitigation outcomes transfer. The implementation framework of the sustainable development mechanism ought to contain three stages: project development and review, project implementation and monitoring, and project acceptance and unit transfer. The authors hope it can work as a guideline for the early implementation stage of the cooperative approaches and sustainable development mechanism to stimulate carbon reduction and further slow climate change.