The invention discloses a preparation method of cassava essence. The preparation method of the cassava essence comprises the following steps: crushing and pulping cassava, filtering under reduced pressure, concentrating under reduced pressure, adding a sugar source and an ammonia source into the concentrated juice, reacting at 100 to 180 DEG C for 1 to 5 hours, adding an organic solvent in volumewhich is 3 to 10 times that of the concentrated juice and performing heating reflux extraction at 45 to 80 DEG C for 1 to 4 hours; and performing primary and secondary molecular distillation on the extracting liquid under a certain condition, wherein the distilled light phase is the cassava essence. The preparation process is simple and the cost is low; and the obtained cassava essence is sprayedon cut tobacco uniformly through a tobacco flavoring process, so the baked sweet and scorched sweet flavors of the tobacco can be highlighted, the smoking quality of the tobacco can be improved, the sensory comfort level can be increased, and the cassava essence is worthy of all-industry popularization and application.