This two-volume set CCIS 2264 and CCIS 2265 constitutes the refereed proceedings of the 6th International Conference on Blockchain and Trustworthy Systems, BlockSys 2024, held in Hangzhou, China, during July 12-14, 2024. The 34 full papers presented in these two volumes were carefully reviewed and selected from 74 submissions. The papers are organized in the following topical sections: Part I: Blockchain and Data Mining; Data Security and Anomaly Detection; Blockchain Performance Optimization. Part II: Frontier Technology Integration; Trustworthy System and Cryptocurrencies; Blockchain Applications.