Lawsone which is the main compound of Lawsonia inermis has been used as natural dye. In the recent days, the functionality of lawsone which categorized as naphthoquinone shifts from its original purpose as dye toward medicinal benefits properties such as antibacterial, antifungal, anti-inflammatory and antioxidant. The aim of this research was to modify the lawsone structure to improve its antioxidant activity by reacting the lawsone with different type of aldehyde which were benzaldehyde, cinnamaldehyde, and salicylaldehyde with the presence of glutamic acid as catalyst. The reaction took place under different catalyst amount of 0 mg, 10 mg, 15 mg, and 20 mg. The 20 mg of glutamic acid resulted in the highest yield of modified lawsone product and was applied to the main research. The structural changes of the products led the wavelength to shift to a shorter wavelength in UV-Vis spectrum measured at 200-400 nm. The modified lawsone product was present, proven by the spots on TLC and the different Rf value. GC/MS and FTIR analyses had detected the formation of the expected product. Modified lawsone product treated with salicylaldehyde had the best antioxidant activity, expressed as IC50 (1427.71±53.057 ppm) with the yield of 49.2773±1.442%. The chosen modified lawsone product had 65% higher antioxidant activity compared to the commercial lawsone.