Biofuel, as a renewable energy, has gained much attention due to the threat of exhaustion of fossil sources and the enormous pressure of environmental pollution. However, biofuels often suffer from low densities and high volatilities, which limit their application in important liquid transportation fuels, for example, jet and diesel fuels. At present, the conversion of lignocellulosic biomass‐derived chemicals has become a promising approach to produce high‐density jet and diesel biofuels. Herein a rapid, green Michael addition reaction is developed for constructing intermediates of a series of new high‐density biofuels with volumetric neat heat of combustion (VNHOC) values. The reactions are performed under solvent‐free conditions with commercially cheap tetrabutylammonium bromide (0.05 eq) and K3PO4·3H2O (0.03 eq) as a catalyst and a base, respectively, to afford products with good to excellent yields of 89%–99%. The theoretical calculation indicates that the VNHOC values of the potential biofuels (up to 39.06 MJ L−1) are comparable to those of most state‐of‐the‐art biofuels and commercial jet fuels that are obtained from fossil sources. This method may pave a new way of investigating high‐density biofuels with accurate structures and high‐energy contents.