Developing high-performance electromagnetic interference (EMI) shielding materials and wearable EMI fabrics is significantly important for the integrated electronics and wearable electronic devices. Herein, we propose an in-situ reduction strategy to construct a high-conductive silver/thermoplastic polyurethane nanofiber membrane (Ag/TPU NM). Benefiting from the intercrossed structure of TPU nanofibers and strong adsorption interaction of Ag⁺ by the unsaturated aromatic hydrocarbons of TPU, in-situ reduced Ag nanoparticles (NPs) can be firmly semi-embedded on the TPU fibers, without needing of binders/crosslinkers in traditional methods, to form the three-dimensional (3D) continuous conductive network, and the resulting Ag/TPU NM exhibits high EMI shielding effectiveness of 95.7 dB, excellent Joule heating performance (202.6 °C/V²) and stable environmental adaptability in high (120 °C) and ultralow (−196 °C) temperatures as well as corrosive solution. These outstanding performances are ascribed to the Ag-conductive networks semi-embedded on TPU formed by the in-situ reduction strategy, which protects Ag from oxidation and therefore achieves high-stability. Meanwhile, the inherent stretchable characteristic and intercrossed structure of TPU NM endow its excellent environmental adoptability at wide conditions. In short, combined with excellent flexibility and high air/moisture permeability, the as-synthesized Ag/TPU NM shows the great potential for applications in wearable EMI shielding protection fabrics in harsh conditions.