The invention discloses road emulsified biological asphalt. The road emulsified biological asphalt comprises, by weight, 10-30 parts of biomass heavy oil, 60-84 parts of matrix asphalt, 4-6 parts of methyl alcohol, 1-5 parts of emulsifier, 0.2-0.8 part of stabilizer, 0.1-0.5 part of acidity regulator and 90-95 parts of water. The emulsified biological asphalt has low cost and excellent performance. The invention also discloses a preparation device of the road emulsified biological asphalt. The preparation device comprises a biological asphalt preparation cabin, a biological heavy oil improvement cabin, an emulsified liquid soap preparation cabin and a biological asphalt emulsification device. The device is simple in structure, simple and convenient to operate and good in effect. The invention further discloses a preparation method of the road emulsified biological asphalt. The preparation method includes the steps of matrix asphalt heating, biomass heavy oil modification, biological asphalt preparation, emulsified liquid soap preparation and biological asphalt emulsification. The preparation method has simple steps and reasonable design and is simple to operate, and the prepared emulsified biological asphalt has excellent performance.