In this short Letter, the structure of a rotating detonation wave (RDW) fueled by biofuel is revealed and expounded. A simulation is carried out under an Eulerian–Lagrangian framework in which the main characteristics of the two-phase RDW are analyzed in detail. The results suggest that a self-sustained rotating detonation fueled by liquid ethanol and air can be achieved with hydrogen addition for combustion enhancement, and a laminated dual-front structure of the RDW due to the effect of droplet evaporation is captured and clarified.