The topic of climate change has aroused increasingly widespread concern around the world. Under the agreement at the 21st Conference of the Parties of the United Nations Framework Convention on Climate Change (UNFCCC), covened in Paris, France (Paris Agreement), which requires all Parties to undertake emission reductions, the developing countries who were once exempted from emission reduction obligations are now becoming more and more important. This study focuses on mitigation actions in China, the largest carbon emitter, as well as the largest developing country in the world. Specifically, we examine Chinese Certified Emission Reduction (CCER) projects. The objective is to compare the reduction efficiency of three types of projects: simple abatement and completely renewable energy alternative projects at the supply side and demand side projects. From market-induced carbon leakage point of view, a dual market equilibrium model was built, with results showing that the key factors affecting the leakage rates are price elasticities of both demand and supply sides and market share parameters. In most cases, renewable energy alternative projects show the least leakage rate while demand side projects show the highest. Sensitivity analysis finds that leakage rates for the three types of projects are more sensitive to price elasticity parameters than market share parameters. Moreover, factors \( {E}_c^{de} \) (electricity price elasticity of coal demand from coal-fired generation) and \( {E}_e^d \) (electricity price elasticity of electricity demand) affect not only the leakage rate of each project but also the comparative results between them. Although our study is based on China, the theoretical analysis is applicable in other regional voluntary emission reduction markets around the world. So, a systematic approach to comprehensively analyze the issue is summarized, based on which, we recommend two mitigation strategies to cope with the issue in offset projects in order to give managerial insights for the government. Firstly, the calculated leakage rates for different types of projects provide a new perspective to evaluate various offset projects, thus helping consider project types for priority validation. Secondly, we suggest to establish an accurate and classified discount coefficient system according to the project types to deal with the issue; the sensitivity analysis is helpful to find the most influential factors. A top-down approach to implement the strategy is proposed.