In response to the problems of insufficient transaction transparency， poor data security， and low market efficiency in Carbon Emission Trading （CET）， optimization methods of blockchain technology in CET systems were reviewed. Firstly， the specific applications of blockchain technology in CET were summarized， including key technologies and main contributions. Secondly， an in-depth analysis of the challenges faced by carbon emission management and trading was conducted， such as data privacy protection and system scalability problems， and optimization methods of blockchain technology were explored. Thirdly， the integrated application of blockchain and Internet of Things （IoT） technologies was studied to achieve real-time collection and secure storage of carbon emission data. Finally， the application of game theory in the formulation of CET strategies and the innovative practices of blockchain technology in carbon asset management were discussed. The research results show that blockchain technology improves the data transparency and security of CET systems significantly， reduces human intervention， lowers transaction costs， and enhances market efficiency. However， challenges such as performance， privacy protection， and regulatory adaptation are still faced by the systems. In conclusion， the application of blockchain technology in CET systems not only improves the systems’ transparency， security， and efficiency， but also provides reliable technical support for achieving global carbon emission reduction goals.