<p>As an environmental endocrine-disrupting chemical, trace 17β-estradiol (E₂) poses a potential threat to public health. Therefore, the development of highly sensitive and reliable detection methods is of great significance. In this work, an ' On-Off-On ' electrochemiluminescence ( ECL ) sensing strategy based on ' stepwise energy transfer ' and ' silver nanonetwork ' synergistic amplification was proposed for ultrasensitive detection of trace 17β-estradiol. Using lanthanide bimetallic metal–organic frameworks (Ce: Sm-MOFs) as ECL luminophores, via the ladder energy transfer pathway ' H₃BTC ( T₁ ) → Ce³⁺ ( ²D ) → Sm³⁺ ( ⁴G_5/2 ) ‘, the energy mismatch issue of the Sm³⁺ emission center is effectively addressed, and its characteristic emission is remarkably enhanced. At the same time, the morphology of s silver nanomaterials ( Ag NWs@Ag NPs ) is rationally tuned to construct a silver nanonetwork, which provides fast electron transfer channels and abundant catalytically active sites, thereby synergistically boosting the ECL signal intensity. In addition, Ag@Bi₂Sn₂O₇ was employed as a quencher. The ultraviolet absorption spectrum of Ag@Bi₂Sn₂O₇ highly overlaps with the ECL emission spectrum of the luminogen, which effectively triggers the resonance energy transfer (RET) process. Furthermore, Ag@Bi₂Sn₂O₇ can capture electrons from the excited state of the luminogen, achieving dual quenching of the ECL signal. The quenching efficiency is reached 66.1%. The sensor exhibits an ultra-wide linear response in the range of 10^− 5 to 10^− 15 M, with a low detection limit of 3.78 × 10^− 16 M. It shows excellent specificity when applied to actual samples such as milk and livestock feed. With recoveries of 95.1%–100.2%, it demonstrates great application potential in aqueous environmental monitoring.</p> Graphical abstract <p></p>