Poly(vinylidene fluoride) (PVDF)-based electrolytes exhibit a strong potential for applications in high-energy-density solid-state lithium (Li) metal batteries, owing to their superior ionic conductivity, wide electrochemical window, and excellent flexibility. However, their practical performance is so far limited by challenges at the Li/PVDF interface. Specifically, the porosity of the PVDF interface induces uneven ion deposition, which facilitates Li dendrite growth, while residual N,N-dimethylformamide (DMF) solvent at the interface triggers severe side reactions with Li. Here, we demonstrate that introducing an in-situ cured highly elastic layer stabilizes and dynamically tunes the Li/PVDF interface. In situ polymerization of thermoplastic polyurethane (TPU)-containing 1,3-dioxolane (DOL) enables intimate interfacial contact. The TPU within the cured layer increases its elastic modulus, empowering dynamic regulation of pressure distribution and contact retention at the Li/PVDF interface during cycling. The engineered interface enables a dense and flat Li deposition morphology to prolong the cycling life. Furthermore, the interfacial layer prevents side reactions between the DMF solvent residues and the Li anode, maintaining an electrochemically stable contact. Our findings demonstrate that introducing the highly flexible TPU/P-DOL interfacial layer is a large-scale manufacturable approach, which overcomes the main barrier hindering the performance of PVDF electrolytes, significantly improving the effectiveness of solid-state batteries.