Voluntary Emission Reduction Projects (VERs) play an important role in helping to achieve climate goals by reducing greenhouse gas emissions beyond what is required by law or regulation. The objective of these projects is to address climate change by mitigating greenhouse gas emissions in a cost-effective and efficient manner, while also promoting sustainable development. However, voluntary emission reduction projects, including China’s CCER (Certified Carbon Emission Reduction) program, have experienced the issue of double counting in relation to carbon credits. Double counting occurs when a carbon credit is counted more than once, meaning that the same reduction in emissions is being claimed by multiple parties. This can happen when a project generates a carbon credit that is sold to one buyer, but the project owner also claims the credit towards their own carbon reduction targets. To address the issue of double counting, this paper proposed a credit evaluation structure based on consortium blockchains to regulate the voluntary emission reduction market.