This report investigates the relationship between ISO 9000 adoption and the financial performance of service firms, utilizing data from the National Bureau of Statistics of China's Economic Census. The study employs descriptive and inferential statistics, including correlation and multivariate regression analysis, to assess the impact of ISO 9000 certification on key financial indicators such as sales, profits, total assets, and total capital. Findings indicate a positive correlation between ISO 9000 certification and financial performance, with certified companies demonstrating higher mean profits. The report advises managers to consider ISO 9000 registration to improve financial outcomes and to focus on sales-enhancing strategies. Research limitations include the absence of guidance for non-registered companies and the focus on older ISO 9000 versions, suggesting avenues for future research to explore updated standards and implementation steps.