This study investigates, the physicochemical characteristics of Sengmaksan (SM) prepared with Liriope platyphylla (LP) that had been roasted for different times (0, 30, 60, and 90 min, denoted as S-0, S-30, S-60, and S-90, respectively) The Hunter’s color values such as lightness (L), redness (a), and yellowness (b) were the highest in S-0, while the lowest was found in S-90. The amount of soluble solid and reducing sugar content of S-60 were higher than the others. None of the samples exhibit significant differences in, their pH and acidity. The total content of phenolic compounds increased with the LP roasting time, but the total flavonoid and total anthocyanin contents of the SM decreased at the same time. The total ginsenoside (Ro, Rb2, Re, Rf, Rg1, Rg2, Rg3, Rh1, and Rh2) content did not show significant differences. The DPPH and ABTS radical scavenging activities increased according to the concentration, as well as with the LP roasting time. The ferric reducing antioxidant power (FRAP) showed trends similar to the radical scavenging activity, but it was more sensitive to the LP roasting time. From these results, the active ingredient in S-60 was higher, and the antioxidant activities of SM increased along with the roasting time of LP.