Small and medium-sized enterprises (SMEs), which typically face resource constraints, require innovative methods to overcome their challenges. Emerging technologies serve as an opportunity to enhance their resilience and are of great importance. FinTech is a collection of these emerging technologies, structured to improve various financial services. This research examines the impact of FinTech on the investment returns of small and medium-sized enterprises using data from financial technology companies within the country. The results indicate that the growth and development of FinTech can significantly stimulate and boost the investment returns of SMEs. These results remain robust and strong after performing a series of stable and powerful tests, including replacing alternative dependent variables, controlling for firm fixed effects, controlling for various time fixed effects, and using the instrumental variable method and difference-in-differences methods. The analysis shows that FinTech alleviates the investment constraints of SMEs, and it does this by reducing information asymmetry between financial institutions and SMEs, thereby improving their investment returns. Furthermore, heterogeneity analysis shows that the impact of FinTech on SME investment is more prominent and noticeable in small-scale private enterprises, industries that lack competition, and organizations with a slow and gradual marketization process. Additionally, these findings have important practical significance, serving as policy recommendations and operating procedures for stimulating and encouraging the integration of FinTech and the domestic economy.