This study examines how blockchain technology can improve accountability and transparency in sustainable finance and use, emphasizing how it affects investor confidence and environmental results. Although funding environmentally sustainable projects requires sustainable finance, issues like data transparency, fund misallocation, and environmental outcome verification still exist. These issues can be resolved by blockchain, which ensures transparent, real-time tracking of fund allocations and environmental impacts through its decentralized and immutable ledger system. The study examines how blockchain can increase trust and transparency in sustainable finance, evaluates how well it tracks and validates environmental outcomes, and highlights the opportunities and problems of integrating blockchain into sustainable finance. Insights into how blockchain-based systems can promote greater trust and boost market participation in sustainable finance are provided by this further investigation into the effect of blockchain on investor participation. In addition to addressing obstacles like regulatory uncertainty, technological difficulties, and data quality concerns, this study demonstrates the revolutionary potential of blockchain technology for improving the effectiveness, legitimacy, and worldwide reach of sustainable finance. According to the findings, if suitable legal frameworks, technical standards, and international cooperation are created to facilitate its broad adoption, blockchain technology may be essential to expanding sustainable finance.