This paper aims to develop accounting methods for data assets helpful to developing sustainable regional economic development within the digital economy. By considering data-asset characteristics such as virtuality and sharing, it proposes accounting treatments and processes for data-asset evaluation and management. Through a case study of Guangdong Power Grid Co., Ltd., the optimized method is evaluated. Results show a 70% increase in data-asset valuation compared to intangible assets, with a 17.8% growth in total profits. The method reduces asset-management costs by 3.67% and amortization by CN¥98,600. These findings highlight the importance of optimizing accounting methods for data assets able to foster sustainable regional economic development in the digital-economy era.