The implementation of the Ecological Conservation and High-Quality Development of the Yellow River Basin (YBCD) can provide the institutional context for economic outcomes of environmental regulations and influences on corporate financial asset allocation. The basic objective of this study is to examine the impact of the YBCD on corporate financialization, analyzing the influencing mechanisms and heterogeneity. Using the data of A-share listed companies spanning 2015 to 2022 in China, this study employs the differences-in-differences method to investigate the impact of the YBCD on corporate financialization. The findings reveal that (1) the YBCD could significantly inhibit corporate financialization and suppress financial asset allocation driven by arbitrage motivation. It will help corporate financial asset allocation shift towards physical businesses, emphasizing long-term development. (2) The YBCD could inhibit corporate financialization by reducing corporate agency costs and fostering environmental, social, and governance (ESG), leading to crowding-out effects on financial assets. (3) The heterogeneity analysis indicates that the YBCD could generate significant inhibitory effects on corporate financialization in non-state-owned enterprises, high-polluting companies, and companies located in regions with stronger environmental regulations.