Although bismuth-based ceramics are promising candidates for the utilization for the electronic industry, it is absolutely essential to make it clear that many fundamental physical and chemical problems lied in the practical materials system. Aiming to understand bismuth-based low-firing dielectrics for the co-firing multilayer ceramic capacitor's application, the interface behaviors between bismuth-based dielectrics and deposited silver electrodes have been studied. It was found that bismuth-based dielectrics show a deteriorated tendency of dielectric properties towards higher silver firing temperatures. Perhaps poisoned in the vicinity of the interface layer, the metallic electrode silver, has been detected by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy for the samples prepared in the higher silver-firing temperatures, which explains why the dielectric data turn to be bad.