The invention relates to biological asphalt and a preparation method thereof. The method comprises the following steps: 1) crushing biomass; 2) carrying out biomass pyrolysis to obtain bio-oil; 3) carrying out atmospheric distillation on the bio-oil until vapor phase temperature reaches 100 DEG C, and collecting heavy components (being greater than 100 DEG C) in the bio-oil; 4) heating the collected heavy components in the bio-oil to a certain temperature and mixing aromatic hydrocarbon oil; and 5) maintaining the system temperature, continuously adding a high-molecular rubber substance, and shearing at high speed to obtain the biological asphalt. By converting the biomass resource into the bio-oil suitable for preparation of the biological asphalt and with combined use of the prepared bio-oil and styrene-butadiene rubber/waste rubber powder, the novel renewable bio-based road asphalt material with more excellent performance is prepared.