The invention discloses an aromatherapy essential oil catalytic burner, which comprises a burner body, a circuit board and a support, wherein the support is used for installing the burner body; the circuit board is arranged on the burner body. The aromatherapy essential oil catalytic burner is characterized in that one side of the burner body is provided with a mounting surface, whereas the circuit board is laterally arranged on the mounting surface. The invention also discloses a catalytic unit applying the aromatherapy essential oil catalytic burner. Compared with the prior art, the invention has the advantages that the circuit board is laterally arranged, and thus, restraint on essential oil emission is relieved, and the essential oil emission area is enlarged. Meanwhile, direct contact between the circuit board and essential oil is reduced, and thus, the circuit board cannot be easily corroded or even go black, and finally, damage caused to the circuit board due to sudden temperature drop and temperature rise phenomena brought by the essential oil is also greatly reduced, and the service life of the circuit board is prolonged.