Abstract: Improving the interfacial bonding performance between textile and concrete matrix is critical to enhancing the flexural behavior of textile-reinforced concrete and broadening its engineering applications. Inspired by the adhesive mechanisms of mussels, a biomimetic organic-inorganic coating was developed for basalt textile surface modification. This coating, a metal–phenolic-amido network (MPN), was synthesized using tannic acid (TA), Fe³⁺, and polyethyleneimine (PEI). The successful deposition of the coating on fiber surfaces was confirmed by SEM, TGA, FTIR, and XPS, respectively. The influences of the coating on the textile-matrix interfacial bonding and the flexural performance of Basalt Textile Reinforced Concrete (BTRC) were systematically investigated through single-yarn pull-out tests and four-point bending tests. The results indicate that the pH value of the TA-Fe³⁺-PEI modification solution is the critical factor governing the morphology and properties of the coating. With the increase of pH value, the coating morphology evolves from discrete particulate depositions to a continuous and dense layered structure. When the pH value increase to 8, the concentration of oxygen-containing polar functional groups reaches its peak, which markedly enhance interfacial wettability of textiles. Compared to the control group, the pull-out strength and pull-out energy of the optimal modified specimen increased by 44.3% and 203.7%, respectively. And the flexural strength of the corresponding BTRC thin plates also improved by 80.1%. Acoustic emission (AE) analysis further demonstrates that the biomimetic coating considerably increases the AE ringing counts, alleviates the stress concentration effect during the debonding-fracture process of the interface, which significantly enhances the energy dissipation capacity of the specimen. This study provides novel perspective for the interface design and mechanical performance optimization of high-performance textile-reinforced concrete.