The rate of maturity-onset diabetes of the young (MODY) is significantly increased by the common I27L gene variant of the hepatocyte nuclear factor-1α (HNF1A), hence achieving sensitive and precise I27L gene detection is the focus of early monitoring and diagnosis of HNF1A-MODY. In this study, we developed a silver-metal organic gels (Ag MOGs)/ K2S2O8-O2 system-based electrochemiluminescence resonance energy transfer (ECL-RET) ratio biosensor for detecting the I27L gene. The novel Ag MOGs were synthesized by simply mixing Ag+ and Luminol at ambient temperature. On the one hand, Ag MOGs could generate excellent anodic ECL signals in phosphate buffer without requiring exogenous co-reactants, which were derived from the Luminol ligand. On the other hand, Ag MOGs facilitated the electrocatalytic reduction of K2S2O8 by providing stable catalytic active sites and enhancing electron transfer rates, thereby leading to enhanced cathodic ECL emission from K2S2O8-O2. We constructed an ECL-RET ratio biosensor utilizing a DNA walker cycle amplification strategy. The biosensor leveraged the anodic ECL emission from the Ag MOGs/K2S2O8-O2 system as a donor and Atto 425 as a receptor, achieving ultra-sensitive detection of the I27L gene within a linear range of 100 amol/L to 100 pmol/L, and featuring a detection limit of 72 amol/L. Therefore, a direct synthesis technique of bifunctional materials with catalysis and electrochemiluminescence has been developed. Additionally, the ECL-RET ratio biosensor provided a universal platform for the detection of diabetes subtypes.